More than likely Animal Crossing and I am ok with that.

Most of those titles you listed support what I said. Those aren't aces at all and like you said, a lot got delayed so... 

Diddy Kong Racing U

Even though it would be a very 90's move, I suppose there's a chance that Xenoblade Chronicles X could be the highlight. Nintendo try to make that game their Final Fantasy VII.

animal crossing or pokemon for Wii U would be Nintendo's best bet but we didn't heard they are developing a version for Wii U. a Star Fox or Mario Maker would be their big hitter for the holidays or both. Star Fox isn't on the same tier with Zelda series so hopefully Mario Maker would be a great game but Nintendo needs to market it properly to get the sales they need.

If you are talking about Animal Crossing they haven't announced one but from what editors at IGN and some other site has said there is more than likely one in the works. Which whould be a be a good canidate to have a "compainion" mobile game that works with it.

Do you really think designing a dedicated games console is as simple as picking up some pieces, sticking them together, and starting to code? It's not just about developing the parts; it's about selecting the right balance of components - getting the appropriate memory speed to suit the CPU speed while avoiding excessive costs. It's about investigations into options such as backwards compatibility, various controller communication techniques, upcoming technologies, etc. And it's about communicating with third parties and their own first-party game studios to determine appropriate specs. It's about investigating new cpu/gpu functions that might give them an extra edge. And they also need to try to minimise the failure rates of components, which adds yet another factor. And we haven't yet gotten into ergonomics, case design, etc.

They all spend a lot of time trying to optimise their system to give the best bang for their buck. It's not just about innovations, it's also about overall design. And truth be told, they start working on the next console before the previous one releases.

The mere fact that you had to use the word "most" means that my point has been made. And by the way, Pokemon titles are routinely announced around April or May, for September release. Are you going to tell me that you don't think the main Pokemon titles could be called "aces"? There's also Zelda: LBW, which was clearly Nintendo's 3DS ace title for the year.

I also find it hilarious that you say "a lot got delayed so..." - considering that it was a sum-total of TWO titles that got delayed, you're very much reaching for a reason to ignore my point, because you know my point is legitimate.

Honestly does Wii U really need some huge unannounced game to release for the holiday? The fall lineup of exclusives is already pretty solid even without Zelda.

Yoshi's Woolly World (June in Europe)
Xenoblade Chronicles X (April in Japan)
Mario Maker
Devil's Third
Fatal Frame V (already in Japan)
Star Fox
Shin Megami Tensei x fire Emblem (Japan)

That's 5-6 exclusives (depending on region) with most of them belonging to completely different genres. One more small/mid-size title announced at E3 (along the lines of Captain Toad) and maybe an eShop title or 2 (along the lines of NES Remix).

PokeMMOn #believe

Probably Animal Crossing (or Paper Mario?).