MMR system will fail because you can't measure skill in this game
there is so much RNG in this game that you wont be able to EFFECTIVELY measure skill.
measure skill through long chases? what about people who just camp every pallet EVER. and never loops
altruism? hooking in front of the killer, what if a killer camps?
escaping? hide all game and get the hatch
etc etc etc. there is to many factors and RNG element to this game in order for an MMR to actually work