Sakurai is really in the right here. At the end of the day, a game's competitive scene is largely a product of mass popularity, and as a developer, you really don't want to make your game niche.
He was even further right in that the easiest way to make the game more accessible while sacrificing as little as possible was taking an axe to the manual dexterity tests in the game. Removing the need to press a shield button after landing every non-G&W aerial and adding that buffer window really didn't hurt depth at all, but they greatly improved accessibility. Making the game as a whole slower was really not necessary beyond the obvious balance implication that the fastest characters are definitely not entitled to be automatically top tier, and I think on some level the development team just didn't give people enough credit for their ability to handle speed (stuff like Lucas/Ivysaur usmash are only useful moves if you don't give people credit at all). It's not really that bad though; Brawl's years of legitimate tournament success show us that it definitely plays out well.
A whole lot of smart design for competitive play went into all sorts of corners for the game (basically all original content adds such incredible diversity to the game), and Brawl really does work very well. The only real problems it has are a few too many "dumb" abuses like infinites and whatnot, ledge play being a bit too powerful, and a few characters who are a little off in balance. None of these issues can really be blamed on making the game accessible, and indeed all of them have counterparts in Melee. Sheik's chaingrab is really just as bad as anything in Brawl like DDD's chaingrab, there's ledge stalling in Melee it's just harder so fewer people bothered (though I don't think it's actually worse, just harder), and Melee has an even worse case of uselessly bad characters at the bottom of the tier list in exchange for having a more ambiguous top tier. The accessibility perhaps highlighted it; most people never really realized these issues in Melee. I mean, I think we all saw countless arguments about how great Roy was which really proved how many people just didn't get the game at all. Brawl was more accessible so even many of the lower skill players were picking up on stuff like Meta Knight being pretty good or being able to execute the stupid stuff that just totally ruins certain match-ups. The effect, of course, is much more widespread in terms of fall-out since when only the better players are picking up on poorly balanced and polished stuff and exploiting it, it kinda looks the same as them just being better than the other players which means the better players don't complain and the worse players do complain but basically are saying that being good at the game is cheap which is of course laughable. Maybe that means, perversely, that accessible games need to have higher standards than less accessible games in terms of balance and polish since more people will be affected by mistakes in those areas and the mistakes will be more obvious. It's an interesting case study.
I look forward to any Smash 4 in any case. I've been quite fond of Brawl, I support the design directions Sakurai chose, and I think he really does understand most of what is required to make an even better game.
