The new power seems interesting, but it seems like Nintendo is spreading themselves a little thin on the power-ups. Of all the power-ups in SMG, only the Bumblebee Mario was given a decent run. It was used in multiple levels, and each level wanted you to do something slightly different with it. After that is where they stopped being interesting. Boo Mario was interesting in concept, but they never did anything with it. It was used in 2 levels; the first of which you used it for maybe 10 seconds to go through a couple barred gates that could just as easily have not been there, and the second level to use it was just a boring race to see how fast you can drift down a corridor.
From there we get to the two Flower-based power-ups of opposite elements. Ice Mario was interesting, I'll grant that, but the time limit was completely unnecessary. Mario gained no added offense or defense in Ice Form. It was purely a mobility power so I don't see why they couldn't have taken out the theme that plays and just let it run infinite. And while Fire Mario was fun to play with, it was so powerful that it HAD to be on a time limit otherwise you could destroy everything in the level. In both cases though you were never really given any time to actually play around with the power-ups since it was a race to finish whatever it was you had to do with them. Any dilly-dallying and you'd have to backtrack and re-gain the power.
Spring Mario was just horrible. I'm sorry, but a power-up that can basically be summed-up as "And this level is hard because your controls suck" isn't a power-up that should make it off of the drawing board. I'm sure that Spring Mario has its supporters, but the bottom line is that this is an annoying power-up. And then there's the Red Star (Flying Mario?). It had a VERY cool level to unlock it where you could fly around the tiny Gateway Galaxy to collect the coins. It feels cumbersome at first, but really flows once you get to learn it... then that's it. The game congratulates you and says that you can use this power in other places now, YAY!! Except wait... by "other places" you only mean the outside area? And I can only use it to reach a couple of 1-up Mushrooms (in a game where 1-ups are rewarded like candy)? Boo!
So yeah. With Mario Galaxy we were given one power-up out of about 5 that got good spotlight time, and now they're throwing 3 or 4 more power-ups into the mix?