We still have no mention of DQX and I figure E3 or TGS this year would be a good time to at the very least reveal the game.
I really think this upcoming winter (Nov. '10 - March '11) will be the test that decides if Wii2 get the pre-planned E3 2011 reveal and Holiday 2011 release or not.
-If sales stay up there and 3rd parties start showing some of the stuff they've been working on by the end of this year, and it looks promising, then maybe Wii will be stretched out till 2012.
-If MS & Sony have nothing of worth rumored to be coming up by E3 2011, (I'm sure MS will want to push Xbox720 if Natal fails, Move succeeds and/or 3D on HDTV picks up) since neither of then can seem to plug the leaks, then maybe Nintendo will risk not getting a jump on the competition and string the Wii out till 2012.
-If Vitality Sensor catches on like WiiFit and Nintendo has one more crazy idea they wanna try out before finalizing the next system, then maybe Wii gets a season pass good thru 2012.
Otherwise I think Nintendo will continue to follow their nose and pursue new things that can't be done on the Wii since it's their ideas for gameplay that push the need for new hardware.