Since there is mini-drought with Wii software (quality software that is), I think that this game will sell much better than it's predecessors.
300K first week, over 1 million by Christmas time. I actually want to say 1.3~ million, but I'll be skeptical.
With the Wii being insanely popular and in the need of a good FPS, MP3 should be able to clear that 1 million by Christmas easily.
By Wii life's end I say it should even sell about 8 million (assuming Wii gets over 80 million units out). MP3 just seems like one of those "must have" titles for this console.
By life end:
- Wii- 100 million+
- Xbox360- 35~40 million
- PS3- 30 million
- PSP- 30~32 million ------------- FAILURE
- NDS- 85~90 million (Skeptical) - FAILURE
- NDS- 100 million+ (Optimistic) -- Success!