As someone who doesn't really care much for getting this system at the moment, I'll try and give my piece of mind and remain civil about it at the same time.
1.) My Wii and Gamecube stuff still have a lot of mileage. I'd rather finish that stuff up first before moving onto a new system.
2.) Backwards compatability. No Gamecube disc/controller/memory card support. If I want to play my games, then in addition to paying for the system, I'd have to buy all my games all over again. That's not even getting into the issues of whether the games are even in the E-Shop, and all the data in my memory cards (seriously? Years of Chao raising on 5 Memory cards gone waste like that?) The reason this is an issue for me is because as the generations go by, and more and more egames come out, less and less of them really interest me. Being able to still play my older games if something happens to my older systems (Gamecube's started failing on me every now and then) is something I try to look for in a console.
3.) The game selection. Going to Wal*Mart, and some other stores, all I really see for the Wii U is ports of games that were already on PS3/Xbox. They didn't interest me then, they don't interest me now. I know this one will change over time with game releases, but at the moment, it doesn't really give me any incentive to buy the system.
4.) The controller. The thing that really boggles my mind with this system is that Nintendo basically decided to make a giant, 2-piece, DS system. I really don't see the logic in splitting a console into 2 screens. That this Ipad is also supposed to be a controller in addition to a screen... that design just doesn't look like it'll work... especially since I like playing fighting games. I've never actually played a Wii U, so please correct me about anything I get wrong about this issue.
5.) Money. At the moment, I don't have money to buy this system, period. On top of that, I've just now started considering getting a PS3 (I'm a little slow with the "Keeping up with the latest tech" thing), and I'm definitely not getting both. At the moment I could probably find a decent PS3 for a good price since it's been out for a while.
There's a lot of truth to that statement Still though, that doesn't apply to everyone. Killer Instinct isn't gonna make me buy an Xbox One, Kingdom Hearts 3 isn't gonna make me buy a PS4, X and Y aren't gonna make me buy a 3DS, and Smash Bros alone isn't gonna make me buy a Wii U.
Well um, that's my 2 cents on this matter.