In an interview with VideoGamer.com
Senior Producer, Brian Pass, over at Activision explained that exclusivity for the forthcoming GoldenEye 007
on Nintendo Wii was because the "[game] was originally on the N64, so there's the nostalgia factor for people that are Nintendo fans" and that they simply saw a gap in Wii's FPS space, saying that "it's not really a console that a lot of shooter fans are playing on. So we wanted to offer them their own first-person shooter that's unique and exclusive to that console".
Don't hold your breath for any timing lift on said exclusivity though as Primary Producer of the game over at Eurocom, Dawn Pinkney, flatly explains that "it belongs to the platform that it should be on, which is Nintendo".
In case you missed it, we have an extensive write-up for the game you can check out right here