Why not have these levels set by the long proposed article evaluation scheme, based on th numbers which that process gives. That carries no deletion implication, but it warns the user that if he views articles below a certain threshold he may just be viewing a lot of garbage.
I thought the long proposed article evaluation scheme worked on a single edition of an article. Either way, it seems like it'd be horribly abused. Wikipedia is not Slashdot. The day we incorporate meta-moderation into Mediawiki the project is doomed :).