As for the announcement, the only way you can't consider it huge is because we all saw it coming a long way, I mean, absolutely nobody doubted that whenever DQX was announced, it would be a Wii exclusive (I really hope that no one doubted it). That signals that the Wii will be the top selling console in Japan by a huge margin, if there was any doubt.
As for the actualy quality of the game, I seriously doubt it would be a game that I could consider good, and it's totally a game that I'm not looking forward to (and I wouldn't whatever platform had it been announced). Let's say that after the hideous DQVIII, I'm quite skeptical (read: I don't consider it possible) that I'll find a good game in the series (and I won't even try, that's for sure)