I can see arguments both ways on things that are technically recoverable but might require lots of download time (like 20GB of games). However, your settings in those games (if not held on Steam's servers; I don't know where they are) should never be deleted by the application. If you're saying that non-recoverable settings and such should go in ~/Documents, I disagree with that, too: things in the Library folders aren't what the users think of as data, but they are stuff that the users will be upset are missing if they uninstall and reinstall.