Here's the thing. I'm kinda interested in getting a Wii-U, but I'm not going to get one until a bunch of good either Nintendo games or exclusives come out on it. Nintendoland (which is more or less the Wii Sports of the system) and New Super Mario Bros. U are the only actual 1st-party titles on the Wii-U, and overall there are only 6 exclusives which aren't shovelware. New Super Mario Bros. U and ZombiU aren't even close to enough to sell the system for my brother and I, we're going to wait until there's actually more exclusives to get.
The other main issue I see with it is going to be the same as with when the Wii came out. The Wii-U is the graphical update Nintendo should have had 6 or 7 years ago and seems to be fairly close to what the Xbox 360 and PS3 have for graphics performance. This wouldn't be an issue and is a major improvement when comparing between the Wii and Wii-U, but this is going to be a problem when the PS4 and Xbox 720 come out. I know that the Wii did perfectly fine without HD and this argument seems really superficial, but Nintendo's both pushing that they're in HD now and the gamepad plus the system's much more expensive this time around ($250 at launch vs. $350 at launch). Unless, they get really creative with the gimmicks on the touchscreen gamepad and take advantage of 5-player offline multiplayer or something, 'cause I've seen that with New Super Mario Bros. U and that was awesome. The 5-player thing really has potential.
I also say exclusives, because ever since Crysis 1 came out PC ports have been taken a lot more seriously and have put a lot more effort into them. The prime examples I can think of are the DmC reboot and Resident Evil 6. On the PS3 and X360 they run at 720p at 30 FPS, while on any gaming rig (like my laptop) they run at native 1080p at 60 FPS. The point being, if the Wii-U (or Xbox 720 or PS4 for that matter) really only has a bunch of good multiplatform games and the good Nintendo games don't come out until much later in the Wii-U's lifespan, what's stopping me from saving my $350 for a while and just getting the (possibly superior) PC port (Or the possibly superior PS4 version, since my brother and I will probably get one)? This is another serious question I have with the Xbox 720 and PS4 and a reason why the vast majority of Wii games I got were Nintendo games and games like No More Heroes.