Everything right now is speculation. Will it be on the Wii U? Only Nintendo knows. Fans guess it's going to be like the Mario Kart games (alternate between console and handheld), use Amiibo, bigger, etc. Nintendo developers are obviously working on it right now, whether they pull a Smash Brothers, and release 2 games (New 3DS/Wii U) that both use something with NFC. I'm sure they've already jotted down ideas, and are working on integrating them into the games. They're supposed to release some news about the series this year, and seriously, I doubt they'll release villager Amiibo given the production numbers they'd have to do (over 300 villagers), so we're more likely to see a return of the cards like the e-cards from years ago, especially since they announced making cards instead of statues for future games. They have wanted to tie the console version into the handheld version since it was first ported to the GameCube (GBA/GC link cable), so they're going to want to try to tie the 3DS/New 3DS to the Wii U in some way. I'm sure whatever release they do will sell at least a million copies. Even GC's less than 22 million install base managed a couple million copies sold.