If adopted, it's unlikely based on past precedent that wordpress.com will keep the link to your designers in the footer (what with them being a commercial site and all). Since you tell users to keep the links (though I can't see a CC licence with the download, maybe I missed it), are you sure they're OK with that?
To be completely honest with you, Matt makes the majority of the theme decisions, and since it seems to tick most of his boxes (blue, rounded corners, more blue) this has a decent chance of getting adopted. It doesn't make much difference whether or not themes have widgets or custom headers (that code would probably have to be rewritten for. com anyway, and any more complex functionality tends to get lost in the transition). It's more to do with whether Matt likes the aesthetics.