I have a possible solution to AFK/DC LP gains & losses! (REDs PLZ LOOK!)
Everyone wants loss forgiven or lower LP losses when your team has an afk, dc, troll, etc. I think I have a solution that wouldn't be too abusive and would be hard to take advantage of.
Leave it up to the 'Other' team for a vote! Must be 3 or 4 out of 5. If they are decent people and they realize what happened and feel the remaining players where worth it, they can vote for the other team to get a 'Loss Forgiven' or at least a lower LP loss. It is like a surrender vote so majority would have to be for it. That way the losing team can't just get it automatic free game but the winning team deems it worthy or necessary for them to get it.