I have a feeling that Nintendo may be going all-out now. That they'll spend 10-15 mins discussing the final Wii U design and features themselves but unveil a huge amount of games for both the 3DS and Wii-U (under a different name) at E3, both first and third party, but that they'll save a few surprise games for their own conference like two or so months later to unveil with the final price and release date of the Wii U (my money's on sometime in November). I really wouldn't expect to see anything for the Wii/DS, except MAYBE Pokemon Black 2 and White 2 or Pandora's Tower. This is how I'm expecting it to turn out, but I wouldn't be surprised to see it turn out a little differently.
As for Nintendo games that we'll be seeing, I'm expecting to see-
Animal Crossing 3DS
Fire Emblem Awakening
New Super Mario Bros. 2
New Super Mario Bros Mii (Maybe some form of communication between the two, I've also got a feeling that this will be a pack-in game, ala Wii Sports)
Wii Sports U
Wii U mini-game package (with Find Mii and the other games from E3 2011)
Pikmin 3
Retro Studios game (I'm hoping for a DK64 sequel, but Metroid, Star Fox or F-Zero are welcome too)
Brain Age (Very interested in the Devil Horns, amazing, seeing as I wasn't interested in the last one at all :P)
Maybe a few minutes of talking about the ideas they've got for Super Smash Bros. so far.
