Sakurai even corrected what the competitives thought was wrong with Brawl and threw them a bone, yet they're still not satisfied.
But he did so selectively; there are a few characters that are much faster in both mobility and attack speed and thus are much more capable than their Brawl counterparts, but he didn't give this change to everyone, not to mention the game's physics all-in-all are a lot different and there are many contributing factors to why exactly the fans aren't pleased.
Saying that he took what was wrong and fixed it is true to an extent because he did alter some aspects in an attempt to please competitive players, but he also made changes that nobody asked for and not many people are really satisfied with.
I just want everyone to feel like a solid character.
I don't care about how simple the game is, how forgiving it is, or whatever, I just want to choose whoever I want to choose and know that if I devote my time to this character, I can get good results because they've been given tools to help make their weaknesses not as much of an issue (PM Ganondorf, DK, Charizard, Ike).
Personally, I'd be fine with Sakurai if he kept Brawl's physics and just buffed the characters that needed it.
I really don't mind Brawl's engine and enjoy wars of spacing as well as the potential for more innovative attack strings.
But it's not a case of something not being like Melee or not being like Brawl, it's a case of this game not being what I was told they were giving me.
It doesn't matter if you rebuilt a character from the ground up if they still can't do what they need to do to compete well at a higher level; giving reasonable buffs to those who need it can pretty much only make people happy.
I'm not saying this will end all complaints because people will always complain, but it would make the game a lot more interesting without tweaking major aspects of the game engine/mechanics.