Ok, let me quickly counter your arguments about the one-star reviews.
"It's too easy"
Mario Wonder is designed for little kids. And besides, even if you finish, I'm willing to bet money that you didn't go through and collect every wonder seed and 10-coin. If you have beat it, then 100% it.
"Graphics are bad/it's too cartoony"
You are the one tripping, the graphics are awesome. You really want to go back to the NSMB days where the animations are super bland? The animations are more vibrant then ever, meanwhile NSMBU is bland. It actually gives personality.
The only reason I don't give this game 5 stars is because of online multiplayer, I wish we could interact with each other more. Multiplayer Versus in MM2 is fun because you can throw people into lava, and in Mario Wonder you can't do that. Besides that, awesome game.