Please notice, this is a rumor, it's not confirmed, it may not be true, and don't shoot the messenger.
I heard from an employee of Activision, who for sure knows more about this stuff than 99% of any of us here, that Infinity Ward wants to develop the next Call of Duty on the Wii but finds the restrictions by Nintendo holding them too much back. It seems Nintendo doesn't allow new maps or gamemodes to be offered (even for free) after the game has been released. Appearantly, Infinity Ward wants to offer these kinds of DLC, but can't, and it's a dealbreaker for them. Activision has been debating this with Nintendo, but Nintendo will not budge.
Now, this seems insanely childish of both Infinity Ward and Nintendo, and I would guess Activision decides if Infinity Ward does a Wii version or not. But there you have it.
