The Wii U has compatibility capability with up to 2 Gamepads.
And then 4 Wii Remotes or Pro Controllers.
That adds up to 6.
I doubt Sakurai would take advantage of that and there are better things he can do.
I think that we have Donkey Kong and thats it for the Series.
I think Sakurai had that as a reason for not announcing a Donkey Kong Character yesterday.
Yoshis New Island will probably define the timeframe of Yoshis announcement.
I hope every character and assisst trophy and item and pokemon returns. This game needs to be as big as it gets to ensure success. After all I dont want it to be a game you can complete and unlock everything in a week its gotta last.