I doubt it but AC:U??? 

(not Assassin Creed Unity for those who'll point that out XD

Gotta be honest, Unity was my first thought. Haha.

There you go, that's an unannounced game that could perform exceptionally well. AC isn't too popular on home consoles though so, like you, I doubt it.

^wasn't City Folk disappointing, and hence the reason it didn't perform as well as it should have on the Wii? I cannot think of any other reason, considering how extraordinarily the console was doing back then. I think a proper follow-up would do well on the Wii U.

I truly believe Animal Crossing could be Nintendo's biggest Wii U title in Japan, but honestly I don't think they have much else... Zelda is no longer a major franchise there (A Link Between Worlds and Skyward Sword did not do impressive numbers by any means) and the other major franchises are all out already.

Splatoon? Mario party 10? ( i think wii party u sold more than i expected)

only game that would top mk8 or ssbu is a youkai watch for wii U.

That or Pokemon.  But imo, Pokemon would need to be somehow reworked for home consoles, a bit of a different take (and no, I don't mean Coluseum or Snap).  Like maybe a Pokemon that is more of a serious take with some more story, set in the pre-Red/Blue timeperiod, immediately following, preceeding, or even during the Pokemon wars hinted at in several of the games (like Gold and Silver).  Could be interesting to have some crafting skills in that one as well (appricorns obviously, but other things as well).  Also, they could then have Pokemon in that time period that don't show up on the Handheld games, but then have some sort of time capsule/travel trading, thus making the two Pokemon game lines connected.  But anyway, enough blabbing. 

I don't see it happening, man.. Not even another Mario game would reach MK8/Smash numbers! :/

Ugh Smash.... just get to 250!

But X gonna give to ya. 

They earned like 100M+ $ on YW franchise... More than enough to have your own building to house 280 developers......