Rep. the source of all evil.
But I really do think a neat "thanks" or "like" system would be good to avoid tl;dr.
No need to count all the thanks or likes a user has(that would lead to useless elitism :/), but that way people could tell "Hey that post must be worth reading".
There would be no "dislike" so no one would go around saying every post not agreeing with his own is bad. :3
Just my 2 cents.