those choices seem a bit limited to me..
but eh
Id want an adventure/platformer title with a bit of depth, cutomization and replayability.
For example Id prefer a game like the phantasy star 'online' series that had you create a character, race and whatnot and send it out there on random quests. There was a story in there somewhere that could be played but it was mighty fun going round with friends.
It would be a good chance to show off how the Wii handles an online environment aswell as introducing some sort of communication with other players [lord knows they cant avoid it forever]
Wouldnt mind a Kid Icarus, zelda clone with a slightly more darker storyline similar to twilight princess [but obviously not] cause it has alot of potential there especially seeing as Pit was in brawl.
and finally to end the nerd factor I reckon that a Pokemon, ouendan or Pheonix Wright game would rock hardcore on wii =B