I'm glad you've came to air out your specific concerns of the game. I've been around long enough to see from beginning to end the various concerns and tribulations for Brawl as a game and as a scene. I won't lie and say there arent glaring issues, but for the most part people are mistaken on what precisely those issues were.
Even though its a tangent, I feel I should address the concern I have with older Brawl players assessments of Brawl, since this experience is something I see listed in assessing smash 4. I have no intention of judging anyone's ability to make accurate assessments when well informed, but unless they were involved with or paid deep attention to its gameplay
at least after Apex 2012, they are not welll-informed. I dont mean to diminish experience or accomplishments that happened before this since itd likely be a strong analysis pre-2012, but in retrospect this is information and experience that only applies to the early metagame.
I use Apex 2012 as a threshold because its a good line and thats when this happened
This as well as other things forced drastic changes to the American scene and the way we viewed the game, which is why most analysis from players before this moment does seem outdated.
Being more specific, heres one example in regards to the punish game which I believe fell under the umbrella of "guessing" you listed. I feel this is an area that is heavily misunderstood by those who never fully explored its depth. "Guessing" is a derogatory way to put it, its called probability maximization. The idea is to maximize probability of one event occurring over another. Once an opponent is hit, you rely on the fact that youll have a greater amount of options compared to their limited amount in order to continue a string. The initiator needs to have a deep awareness of each players options and an awareness of which one the opponent likely to choose based on the habits of a typical person and the player. After their choice the initiator may be right or wrong,
the point is that as the initiator youre going to be correct a disproportionately greater amount of the time then your opponent, and as the game plays out this works into your favor. Not only is this a relevant skill in games like poker, its the closest thing to actual real life decision making, where outcomes are not predictable but you can still have sway in their probability.
Runaway tactics were more common in the early meta-game and could be viewed as leading to more guessing. But as these started losing to those who improved on their ability to string opponents as just described, it became significantly less popular and when attempted would fail to net victories. I won't delve into every concern listed since this isnt a thread about Brawl, but I believe we're not in agreement on how the current meta-game functions. I just wanted to provide one example of what I meant.
I guess the last thing Ill do is go over thing things mentioned in regards to smash 4.
In regards to aerial lag:
In melee unless youre fox and falco, or maybe have something like samus' up-b, Im fairly certain landing into the ground next to an opponent in shield grab range with an aerial leads to punishment against a good opponent regardless of l-canceling, correct? I think people arent accurately assessing how much lag aerials had in Brawl, which was still a fairly aerial intensive game, and how players went around this. In an environment that isnt as heavy as melee short hop aerials typically have the trait (and common use) of being auto-canceled, in addition to having a greater ability to weave in and out with more time spent in the air.
In regards to group mobility:
This is an interesting concern, but I think looking at approach options in isolation leads to issues in how the offense/defense aspects of the game will work, and should be weighed against the games defensive mechanics. As compared to Brawl, Sakurai took a knife to the games more defensive tactics such as planking, and many others which tended to be more character specific (I mentioned some in an earler post), and added a few small but nice touches to offense such as being able to shield right out of dash and Pivot Cancelling. None of this can determine how the ground game will play out, but what I can say confidently is that defensive options are weaker than Brawl's and its offensive options are improved.
Lastly in regards to Brawls problems, unfortunately the most significant answer is obvious (but one not yet stated). Metaknight created a massive divide in the community. It led to many other issues that were never able to be resolved and turned the community in on itself. Even after Brawl made an attempt to swing back, metaknight inter-fighting prevented this from happening.