Also, the game bafflingly allows the team to commit suicide in co-op by accidentally pushing the A button to idle in a bubble. 
This happened last night while my wife and I were playing.  It's one of the few controller-throw-inducing-rage moments I have had with the game.  

Single player, I'm loving most of the game, as much as I enjoyed the DS version at least.  I searched around, found a warp cannon on my own, and am working through world 8 already.  Mostly so I can unlock the "save anywhere" feature, which I also thought was a stupid unlock on the DS.  Then I'll probably go back and get every coin, just as I did on the DS.
The new motion platforms and twisting mechanics are spectacularly done.  It's a little bit of the old "rub your belly and pat your head" challenge, where I really have to focus on the right angle and timing my jumps.  One castle, I think world 7, has you riding a crane-like platform, while bob-ombs rain down from both left and right.  It was an intense challenge, and very rewarding when I finished it.  

Overall a great game.  But once again, the Wiimote seems to leave something to be desired.  Seems like just another button or two (spinjump, maybe separate hold/run) would make the controls perfect.  But I guess they did the best they could with what they have.