Something that would slightly influence search results to help you zero in on the better posts that match what your looking for.
You know, back when Google Groups was still a thing, they added up and down votes on posts and everyone was convinced that they didn't do anything.  To test it, I punched in some phrase like "Gottlieb clear coat" and had GhostMouse downvote the top results something like 20,000 times over my lunch break.  Sure enough, a couple of days later, the top results were sent far to the back.  
But the most unfortunate result was probably 10,000 posts on rec.games.pinball a year from people going, "why did someone downvote my last post?  I thought it was a good question."
Do we really want that here?  We already had "respected" members acting like pieces of garbage with the half assed system we briefly had in place.