I can see the benefits of having 'all titles' as default, but I'm erring towards keeping things as they are. Either that or having 'all titles', but listing CGC stuff separately in some way. Perhaps all 'notcrap' followed by 'iscrap', and somehow making that segregration clear.
Authors don't do CGC entries in the same spirit as their 'proper' games, and for most of the CGC's history, were never stored as part of the same archive. It wouldn't bother me, but I can imagine some authors don't want to be judged equally on their throwaway fun stuff.