Heya. Gonna respond to this in a sort of quickfire bullet-point style, because I like your attitude and there's a lot I want to say (I live for Mother character talk) but I tend to ramble a lot so I'm going to try and make sure this doesn't get too crazy:
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pretty sure jab hits behind (as well? I don't recall ever hitting with down tilt behind me but maybe it does)
-f.air is the only safe landing aerial he needs really, when he has a f2 jab, f3 down tilt (both with excellent hitboxes), and a really good ftilt. F-air puts the pressure on the shield as he comes down and the other grounded options he can do to follow up after f-air further help to alleviate the pressure secure Lucas' landing way more than Ness can secure his - that f-air faces forward in comparison to say, Ness bair is a godsend in this regard, because it means he can jab/dtilt without having to turn around
-Whilst ftilt has "noticeable" lag, I wouldn't call the move laggy by any stretch. The general point of ftilt is to safely poke at a shield and/or reset the spacing that Lucas operates best at, in these regards the move is extremely good and due to the function of the move, the lag on it isn't troublesome. If you mis-space it on block or something then yeah it sucks, but that's why you shift backwards slightly with it/use jabs/dtilt instead. Dash attack admittedly is just a bad move, which isn't dealbreaking, Lucas has different (and strong...ish) tools for the midrange.
-The fact that Lucas relies so much on his grab in S4 really upsets me to be honest. Probably the worst thing about him is being over-reliant on a tether grab (which is not good... you don't have to read this if you are prepared for it, and you really should be) to actually do anything at all outside of just poking around.
-100% agree that Ness' offstage life does not make him unviable. It's a core weakness of the character but there is juuuust about enough wriggle room with it to make it not awful. There are significantly worse recoveries in this game. The idea that Ness' recovery makes him unviable is because unlike Cloud, the rest of the character is supposed to be bad, but this is so blatantly untrue that I just don't know why people still believe this so feverently. I guess many people just don't have an interest in learning about this character in S4, which is a shame but I can understand why he's low-priority for a lot of people.
With regards to why Lucas hasn't been getting results since release, there are a few reasons:
-for a long time, he was actually pretty mediocre. Winning neutral was too much risk for not a whole lot of reward and he had no real trump cards or standout strengths to make him an attractive time investment for many. I feel this kind of holds true even now to be honest, but way back when, the risk-reward balance was quite unfavourable indeed.
-he was released with Ryu and Roy, two characters that were both really hyped at release and Lucas was just kind of... there as well? Not many people were willing to explore Lucas with Ryu and Roy doing the rounds except for his old Brawl players. And there weren't many of them either, because he was not too hot in that game.
-He got his important buffs the same patch Cloud came out, so again... nobody really cared
-And so we get to where we are now, with very few high-level players playing him and those that are being really obscure anyway. And there's still nothing "wow" about him to most people, he still doesn't have much to offer the player looking for the easy win (which is pretty much everyone except character loyalists, who ain't picking up Lucas for obvious reasons lol) or just anything interesting about him in general, being a slow, reactionary and non-classic character who can't play flashy or aggressive or "hype".
So maybe that answers why he has no results... nobody plays him except a small group of high-level players who don't go to anything. Kinda sucks.
Lucas' matchups can be very polarised imo and with the exception of a few of them, Lucas lives and dies by how well he can force the other character to approach. If he can't, he hasn't got a hope in hell. If he can, he might do alright but might still lose in theory. Some higher-tiered characters are def worse for Lucas than Ness imo, I really think Ness is noticeably better in matchups such as Sheik, for example.
Why people think Lucas is a sleeper threat has to do with just how well he can play Smash 4, at least in the neutral, and perceived greater consistency due to his neutral and a pretty decent disadvantage state. But like everything about him, neither his neutral or his disadvantage are particularly amazing, they're just decent. (His advantage state is actually pretty bad.) Then again, people give Lucas' recovery a lot more credit than it deserves imo so maybe opinions on that will start to turn when the collective realise just how easy it is to intercept for the majority of characters. His inconsistent advantage state is a serious problem.
I do think he is a better character than Ness... but I do appreciate someone else fighting Ness' corner to show that he is actually still quite a good character.