Nintendo might reveal a megaton for the holidays, but i think that's not going to happen.
So, based on what we know for sure, it's either AC or Pokémon that will a big representation in the showfloor.
AC's presentation would look cute but not really engaging.
Pokémon? Unless it's something mind blowing, i don't see it being the center of the showfloor.
Personally, and again, based on what we know, i don't see one of those two games taking center stage at the showfloor.