I've never heard of this Grezzo, and didn't even realise Nintendo outsourced its games to other developers but if it's done well and frees them to work on other games, then great.
Re: the box art, I've always liked it when they go minimal as with a lot of past Zelda box designs so could have done without Link and Epona, but that's a major nitpick. Agreed though, hope it gets the shiny treatment.