In a few months the Wii U will be here and hopefully by the end of E3 we'll know pretty much all we need to know before it launches. I've already decided that I'm buying one, pretty much no matter what they say at E3, but that doesn't mean I don't have my doubts. There are some crucial things that Nintendo need to ensure for the Wii U to be a success.
The key thing is third party support. Nintendo's first party content is stellar and I'm sure there'll be a strong first party game or two for launch but what they need is long term third party support. Their launch and immediate post launch third part support is great: Assassin's Creed, Battlefield, Batman, Aliens, all great looking games. What Nintendo need to do is secure some other big names, Bioshock, Resident Evil 6 etc. but also get long term third party support so they can keep up with Sony and Microsoft when they release their new consoles.
Second of all they need to consider price. The Wii U could easily be very expensive, that controller does not look cheap. The real issue is that in terms of specifications and power, aside from the controller, it is only likely to be about as good as the current Sony and Microsoft consoles so it can't really be allowed to cost all that more than those two do.
The other key area of improvement is in it's online capability. The Wii is severely backward with this, it doesn't feature anywhere near the same level of multiplayer functionality as its competitors and the Wii U seriously needs to catch up. Also it needs to offer more entertainment. The PS3 and 360 feature things such as TV services, social networking. Lovefilm, Netflix etc and the Wii, again is lagging behind.
Ultimately most of the details like this will probably be revealed at E3 and the rest will become clear as the consoles launch draws nearer. I for one have high hopes for the Wii U and can't wait for its launch.