The deck sharing web app could need some serious polish (if not rewrite as a modern web app). Something like fork/pull requests and diff would be awesome. That would encourage people to contribute back and fix bugs in the decks.
I don't know about licensing/copyright of the decks.
I don't see any licensing or copyright terms in the list of shared decks, are those usually specified within each deck? A web search turned up this discussion, http://lesswrong.com/lw/k7a/proposal_community_curated_anki_...