I'd rather see MMA without a points system. The pay structure could be $x to show, $x for finish to encourage fighters to go for the finish instead of coasting to a victory.
If the fight went to a decision, I'd rather see the fight judged as a whole- with no rounds, just one fight.
Criteria for judging would be aggression/ trying to finish the fight and damage- that's it.
Edit: didn't read closely, thought this was about scoring fights, not ranking system.
My solution to that is tournaments. People whine about injuries and such and say that many fights would be cancelled due to injuries, etc.
I say tough shit, make that part of the sport everyone knows well in advance when the fights will be, prepare accordingly.