What I think is "mediocre" is the Gamespot review on this game.

User Rating: 9.5 | LostWinds WII
A very original game that has "great art direction" written all over it. Great graphics, great music, beautiful fantasy world, makes my daughter smile with every little achievement. Making the most out of the Wii controls LostWinds is a game you'll love to play with your kid, each controlling the wind or Toku, the child hero. I can't wait to see what are they cooking up for the Lostwinds sequel.

Much is said about the game's lenght, but to that I'd say there's alot of full retail games out there who pale in comparison and are just about some more minutes longer. It's amazing how much they managed to pack in a 40 MB download. And besides, if you devote some more time exploring hidden corners and experiment more with the 3D elements in the game, you'll be ending up playing a lot more than the 3-hour timespan so argued about.

In my opinion, this game sets a welcome standard on what Wiiware games should be for the 10 dollar pricetag.