Zucas on 24 March 2008
Alot of Wii's "bigger titles" in 2008 probably will be announced at either E3 or individual companies "Gamer Day" type events. Although we do know a few already:
Fatal Frame IV
ToS 2
Wii Fit
Disaster: Day of Crisis
Monster Hunter 3(possibly in Japan for 08)
FFCC:TCB(possibly in Japan for 08)
And there are a lot more titles that I wouldn't call mega hits but should really still be big and help the lineup. I can't speculate what else will be announced but I do know titles such as Red Steel 2, Pikmin 3, and a few more will probably really pump up that lineup.
