Well the game has been getting 9's from pretty much every major publication so it's not really surprising. But after reading about all the different reviews the game easily sounds like a perfect 10 to me. The biggest problem reviewers are having is it not a traditional Mario Platformer, but instead Paper Mario with Platforming instead of turn based battles. Now I agree that this is a valid complaint for many, but for a huge Paper Mario fan like myself, I could care less.
When I first read about the game at last years E3, I was expecting it to be just a spin off of Paper Mario with more Platforming and so it wouldn't be like the other Mario Platformers. And now when I read these reviews, it sounds like the game ended up the way I expected it to all along, so I'll have no problems with it.