Generally speaking, I think it is dangerous to base the cocneption of the game on the sales it will do. Of course, that's what companies do, but for Zelda, a bad game which is the result of choices to make the game more "casual gaming" playable can let fans on a negative point of view considering the franchise, so it will impact the sales for the next games, and the image of Nintendo.
Yoshi's the best of the beasts