I hear the complaints about it being chaotic when there is more than 2 people playing. But I think that is more a testament to the ability of those people working together. Me and my friends had very little problems with any chaos.
My only minor complaint is that they should of had a 4th different character. Mario and Luigi look different enough from a distance but the 2 toads are just a color change. And that becomes confusing when you use different power-ups that change Toad's color scheme.
I dont understand the "Nintendo is lazy" comment. The game is selling tons. People are having fun playing it. If they didnt it wouldnt sell.
I guess there will always be people that have different tastes :/