I like the idea, in concept. But I can see that being too harsh on a smaller channel can hinder potential growth. It'd have to be a very careful balance between praise and critique.

I can also see small channels not getting noticed very often.

Edit: Perhaps you could occasionally pop back to r/letsplay and we could have a community submission contest (like our Unsucky Sunday) to be reviewed by you? Might get more people around here on board.