Come on. The only reason it will get mediocre reviews is simply because it will be a mediocre game. Activision is milking the franchise hard, and they know that even if the game will be bad, the nostalgia factor alone will guarantee that it will still be a profitable title. Lets be honest, even by today standards it looks as a mediocre FPS at best, and the graphics are sub MP3. The multiplayer could be good, but again, not groundbreaking seeing how limited online play can be on the Wii.
Sure, it could become a surprise hit and score in the 90% region and sell like 3-4 million copies, but who are we kidding? I actually have more faith in the DS version, at least n-space has a pretty good trackrecord when it comes to DS FPSs, and that version looks more like the original did 
Vote the Mayor for Mayor!
