Are these in Extras? If so you should be able to use the star rating to determine whether people think they are any good.

Having the ratings and feedback info integrated in the Application Manager (or some App Manager) would be good, someone needs to do the work though.

Going back to broken apps, it should be possible for those that require fixes and have no active devs to simply be downloaded (the source), fixed and then resubmitted, assuming there's someone who's actually interested in them.