I wouldn't mind if Treasure is behind the game. They've worked on a Wario game before (Wario World which was decent) and they're quite proficient in creating 2D games. Smoke39 mentioned Mischief Makers a few posts above which was also made by Treasure.
Now I'd agree on that. Since Treasure is amazing at 2d games, they'd be able to pull it off. And since the Shake gameplay mechanic, does sound similar to Mischief Makers, Treasure would easily know what they're doing and how to pull it off.
Of course come to think about it, Treasure could actually be behind this game. A few months ago we heard that they were working on 2 games for the Wii, and one of them was hinted at being a sequel of some kind. Now a lot of us were quick to come to say a Sin and Punishment sequel, but what if they meant was a spiritual sequel to Mischief Makers staring Wario. Similar to how Bleach DS was the spiritual sequel to Yu Yu Hakusho for the Mega Drive(Genesis), and Ikuruga was the spiritual successor to Radient Silvergun.
Oh well, as long as it's either Nintendo R&D1 who made the previous Wario Land games or Treasure, we know the game will be good.