GameSetWatch thinks so:

...it's odd - by being original, I feel like Rare has made Viva Pinata even less sale-able that an average family platformer would be on the Xbox 360. Which is tragic, because it's a much, much more interesting game - not the character-based banjo Kazooie/Conker clone which I think a lot of people just presume that it is.

I've put in a few hours on Pinata Island and I think the game is freakin' great - it's a mish-mash of of Harvest Moon style gameplay with Pokemon's gotta-catch-em-all focus and I love the result. It really is a shame that this game isn't selling like hotcakes. I'd like to think that there's room in the 360 library for some colorful, quirky, games, but maybe the audience just isn't there yet.