I wasn't going to reply on this topic again but since StoicPhantom put so much effort into their post, I figured I should give it a response (SP, you don't have to feel obligated to reply to this; consider my disagreement food for thought instead of an attack on your position).
I sense a lot of resentment in your post. It seems to me, and feel free to correct me if I'm wrong, like you're a pretty good WiFi Zelda and you're probably reacting against people who try to downplay your skill because of how many reads you make and the fact that you play online. It doesn't make sense to you because you have success online, so you don't believe in the idea of "theoretically sound gameplay."
First of all, I'm sorry that people have downplayed your skill and your game mode. Truly, on behalf of the smash community. Pre-pandemic, it was unfathomable to place weight on the online mode; during the pandemic, it became a necessity, and tournaments died. This sudden shift was something very difficult that we underwent together as a community, and somehow, today, we're still standing on the other side. The transition is something to be proud of given how smooth it's been, but we look back today on online with some heavy reservations. For that, I understand your (sort of intense) viewpoint and I'm sympathetic to the feelings that led to it. Everyone has a way that they like to play. Online, for all its problems, is a valid way to enjoy the game and be good at it.
The fact is, though, that people
do appreciate the value of online and the skill necessary to succeed online. In fact, you can't be good in smash any more these days without playing online just because of how many characters there are and the rate of meta acceleration; you can't be ready for everything without that practice. Online preparation is just as important as in-person preparation unless you have very high adaptability naturally (Mkleo for instance is a very adaptive player and can learn matchups as he plays them, with a few notable historic exceptions; acola is another. One plays online, and the other doesn't, but both have the skill of adaptation).
What you're describing doesn't happen that much. Top players don't go online, lose, then disparage online because it doesn't conform to their expected style of play. If they complain about Quickplay, it's usually just the normal trashtalking that they do even offline (believe me, it's mostly salty banter), or expressing frustration about the diminished value of reaction.
Actually, though, most top players play online a lot. Fatality spends a great deal of time on Quickplay. Tweek exclusively plays online, even if it's an arena. And so on.
And I think there exists a parallel in fighting games as well. I keep seeing people go on about the "proper" way to play, like only using moves that have a high percentage of success or talking about playing MUs right or wrong and others. And yes, I suppose there has been lots of study in how to "properly" play fighting games. And people study extensively the "proper" way to do things and practice against other experienced fighters. They assign each other ranks and positions of status within the club. And they all of course develop a certain sense of elitism that they're better than anyone that doesn't go about things the way they did. At least until they venture outside their club for a bit.
Most really good players (the top players whom you're talking about) are really good online too. There have been a few historically, like Samsora, to whom this hasn't applied, and a few who refused to play like DarkWizzy, but for the most part, being top-level offline translates to being top-level online.
You might be surprised to hear that most of us also believe that it goes the other way around too. Most players who are really good online are good offline too. Sparg0, Miya, Acola, and so many more. This is because online and offline share a skillset that's important to smash. Adaptation, spacing, edgeguarding, reads, etc. There are countless things that are important in both modes.
But of course there are differences, online isn't just offline with training weights.
Online diminishes the value of reactive ledgetrapping and reaction-based setups. If players can adjust to this going from one to the other, they can be good at both. For some players, this isn't entirely possible. Scend is one of the best online players, but his reactions are a bit slower, and he plays a character particularly vulnerable to reactive setups, so his offline results go down in accordance with that gap. He's still great offline, but comparatively worse compared to online.
sparg0, on the other hand, was struggling to beat top players offline at first, but then MKLeo gave him advice on how to mix in reaction in his playstyle; sparg0 took the advice, found that it was within his capabilities to react the way top players do, and then started beating everyone after combining the skillsets.
Acola and Miya have translated their online success directly to offline without such intervention too.
Everyone has a different combination of skills. Ultimately what we're here to spectate is tournaments, not WiFi matches. That's why we care so much for tournament results and sometimes (wrongly) discredit online entirely.
When they face an online opponent that doesn't quite go along the familiar patterns they're used to, things begin to change. The half-hearted movements they call "feints" get steam-rolled by an opponent that neither knows nor cares about safe movement. The petty tricks and mindgames go ignored by someone that is only concerned with doing what he wants to do.
What you do here when you run into someone who doesn't have high-level movement is lower the level of your play. If you don't play to your opponent's play you'll always lose, no matter how good you are. Most smash "trained fighters" know this. This is true in smash and also most competitive sports. Dabuz, Fatality, and Marss (who are all great online as well as offline and play a lot of online) have talked about this extensively on their streams; their opening move in any match is to assess the level of their opponent and play at that level. If you don't, then yes, you're making feints for no reason, you're waiting to react to something that won't ever happen.
If you know how to react to ledgeroll and ledge jump and always prepare for it but your opponent never does anything but getup attack, then of course you're going to lose. You have to adapt to the level of play. (For tournament players who play in long brackets and get top 8s, this is actually an essential and under-discussed skill for a completely different reason. You can't play your best earlier in bracket because you
will wear yourself out)
He doesn't have to prepare for his opponents because he can properly adapt to who he's playing against in the moment. He can do that because of his experience playing all kinds of different opponents and their playstyles online.
Adaptability is an important aspect of skill for sure, much more important than preparation overall. But this is actually one of the things that I felt was missing from Onin's play as I was watching.
He wasn't as good at adapting as other players. In fact, he rarely needed to adapt. He used the same gameplan against everyone. If his opponent started adapting, Onin's adaptation generally consisted of placing a block to rearrange the stage in such a way that the adaptation would no longer matter. You can call that some kind of adaptation for sure - it certainly takes knowledge - but it is something uniquely available to Steve. It's not that Steve is particularly bull****, but you have to account for a character's uniqueness when discussing them.
This is generalizing, because obviously to win a tournament of this caliber you need some level of normal adaptation too, and Onin has that (unlike someone like Jake, for example; it's no exaggeration to say that Onin is a top 10 player right now, or better, which definitely requires adaptation), but you can still draw Steve-specific conclusions from observing the trend.
It's the same as Min Min being able to ledgetrap without any risk from center stage. This is something unique to Min Min and she doesn't need to prepare for your character to be able to do it (except in a few cases, e.g., Pikachu); there are few mixups available for you, so in this situation you must play Min Min's game.
In neutral, and advantage, and sometimes disadvantage, Steve can set up his gameplan and you have to play the game his way.
Does this mean that Steve players aren't skilled or didn't deserve to win? Of course not. It means that they can win without knowing how to DI Wario combos, or how to play reactively against a Fox b-airing their shields, because they can avoid those situations with the right block placement. But that's not a knock on their skill.
We're (or at least I'm) not trying to take away from the skills Onin showed in tourney -- great ledgetrapping, impeccable reactive burst (not an online skill, really; Onin has plenty of offline skills too), very creative setups, juggling, etc. With all those skills he's definitely top-10 caliber. We're pointing out the areas where Onin's skill was deficient and having a discourse on Steve based on those gaps. Onin was clearly not particularly skilled in disadvantage drift, neutral adaptation (though it's worth noting how well he spaced around Game and Watch shield in Grands), or top-level MUs. His other skills were sufficient to win (which I suspected they would be going into this tournament). This doesn't mean that those other skills are more important or impressive, but we can use this unique combination of player strengths and weaknesses to say some important things about his character.
I really enjoyed watching his play and that's not something I've been able to say about Ultimate for a long time. It was refreshing to see genuinely good defensive play in a meta that has been taken over by mindless aggression and mashing. Actual defensive movement and micro-spacing
But we see this all the time from players like Mkleo and Dabuz and even acola (who is a wizard with spacing!). Defensive movement and microspacing. It's a cornerstone of the meta (so is mashing, though, you're right).
I wouldn't characterize Onin's playstyle as defensive either. If you hear other Steves talking about Onin, they often mention how he's aggressive and scrappy ("mashy" as Onin has characterized his own gameplay at a few points, though there's absolutely nothing wrong with mashing). Onin's defensive play was regardless pretty clean and interesting to watch when it happened, but it's strange to highlight Onin as a bastion of defensive gameplay. You want tactical defensive gameplay, you have Dabuz. You want crazy setups and aggressive burst, you have Onin.
Bottom line, you either win or you don't. There is no "not playing properly" or using "unfair tactics" or whatever other nonsense. There is only what works or what doesn't.
A fairly reductionist way to look at things. Read-based play has always been less consistent than reaction-based play, but this doesn't mean it's not viable at all to make reads. When we say that you should play properly, it's because we know that it works when you can react to things more often (reactions are guaranteed and reads aren't). We're not saying that you can never up-smash to call out an aerial opponent or something--knowing when to go for a read is an important part of being a top player too. Some top players specialize in reads (Marss, ESAM), while others play it completely and overly safe (Tweek), while others are in the middle and do plenty of both (Leo, sparg0). And, of course, "playing properly" also includes other things, like DIng moves properly, knowing at what percents Wario waft comes online and avoiding it, etc.
You can win a matchup against a top player without playing the matchup properly. Everyone knows that the best way to beat Mario if you're playing Lucina is to space your sword at the tip with plenty of microspacing and safe setups. You get one zoning n-air or f-air and then go to town in advantage and destroy the Mario. Not playing this matchup properly would entail not trying to space and instead getting up close to Mario trying to grab or something and set up a win that way.
You can also win a matchup without knowing how to DI a combo. If you die every time you get hit by Bayonetta side-b, but you outplay your opponent such that you only get hit by it once a match, then it doesn't matter if you were playing properly - though it still stands to reason that you'd do better if you did.
Can you win playing this way? Absolutely. It isn't the best way, but you can win.
Watching talented players who find the best way to surgically destroy someone is entertaining. When sparg0 3-stocks Tea because he knows the perfect drift for every situation and leaves Pacman helpless with 0 options, man, that's really fun to watch. That's not to say that more brute-force options can't be entertaining, though. Plenty of people like watching Kola who is notorious for having next to 0 preparation for matchups.
Also worth noting is that there is another class of players--those who know how to play matchups properly but still choose to go for hard reads that don't conform to that knowledge. These are players like Fatality and sometimes Marss. Their results are usually pretty mixed.
Finally, I want to end this part on the note that I think you're finding the wrong example for your point. Onin isn't a WiFi warrior with unconventional, overlooked tactics who is suddenly beating everyone in their "dojo" and proving that top players were shams all along (which, as an aside, is honestly really crazy to hear as someone who's played against the best on WiFi and played top players a bunch in person; top players are top because they have insane reaction times and are so quick to catch habits)--if anything, that's already happened on a different level, because you can say that about Miya or sparg0 or Kola. They were WiFi warriors who played the game in a wildly different way and changed the ongoing meta when they arrived on the scene.
Onin, instead, is the peak representation of a setup and resource character who plays differently from any that smash has seen. There is much to be impressed about with his play, but I don't think he fits in the narrative that you're presenting, on basically any axis.
this mind-numbingly boring stagnation that is the current meta.
The meta literally changes every week at top level right now, it's insane and impossible to keep up with. Dabuz, Sonix, and Riddles alone have come up with so many innovations in the last few weeks that it's mind-boggling. It's not just Onin. I see something completely wild every single tournament, and usually dozens of somethings.
tweek & switching to braindead characters
Tweek has held top 10 results (mostly top 5) with a dozen different characters. Switching to the so-called braindead characters actually always
hurts his results instead of boost them. Leo and Tweek have had
worse results after going full Aegis. There's a lot more to it than the simplicity of the character. I actually am having a hard time understanding which top players are phony or phoning it in by your framework because all of the ones we typically see (Riddles Sparg0 Tweek Leo Dabuz etc) are just
so good on all the axes you mention.
There is an argument to be made for Maister lacking some important smash fundamentals that shows up when he uses any non-Game-and-Watch character, but even then, Maister is pretty similar to Onin in that regard. A character master instead of a game master. Nothing wrong with that, both are phenomenal regardless. Would be really hard to say that either is "phoning it in."
You have to qualify this a little bit, at least. Outside of Onin, did any of those top Steve players get a win above their seed?
Regardless, while I hold that Steve isn't a problem and isn't unfair, the data is actually fairly suggestive in this regard.
Steve has the highest winrate online, and is also the most played character online.
Steve is the most played character offline in top brackets, and also has the highest rank on OrionStats.
Two Steves won big tournaments yesterday on opposite ends of the world.
Steve is making a compelling case for being the best this game's ever seen. I don't buy it or think that Steve is top 5, but the data suggests that it's possible.
NairWizard saying a guy that just won an s-tier event had no idea how to win certain mu (other than maybe that sora at the end) is just salt talking
or 
