Well a Wii version wasn't officially announced - although it did appear on the website for a while.
I think the Wii version was an after-thought. Also, they might take the Wii version is a slightly different direction to allow for a more immersive experience with WM+ stick handling controls. If it's not the same game it makes sense to release it at a different time.
WM+ might have also delayed this game - but not for a whole year.







