They did an excellent job on Wario's animation - I was really impressed at how smoothly he changes direction during a sprint and small touches like his belly shaking after he lands a flip is cool as well. The gameplay just looks fantastic. It seems you'll have to master all of Wario's moves in order to reach all the hidden treasure throughout the stages.
My only beef is having the shake the Wiimote while holding it in classic mode... I don't like that. I haaaaaaated it in Super Paper Mario. Hopefully, you won't have to shake as violently for the motion to register like in SPM.
Other than that, the game looks great. Insta-buy for me for sure.