Yeah, good points! We are still figuring out the norms for the discussion, and how it will ultimately be converted into pages.
I'm a bit torn on making things mandatory, since that's annoying, and I can see many instances where people downvote because the content is just obviously bad, and nothing needs to be said. Shouldn't be an issue for a while.
We've spent a lot of time thinking about alternatives to "Like", and we've considered "high quality". Quite possibly we'll move to that once we add "dislike" and other voting mechanisms.