MMR, Dailies, and Queue times.
While I have my fair share of complaints about the hidden MMR system I'll keep those to myself as it's a work in progress and I don't want to bash the system until it has had its rough edges smoothed out.
This feedback is in regard to the combination of killer MMR and dailies respectively.
By giving killers independent MMR from each other as a killer main it bothers me when I get a daily for a killer I don't play often. It ruins the queue times for those killers and makes the games nearly unplayable and I know that it will force some of the newer players to quit out of feeling bullied. Anecdotal evidence could even be seen today. First game after work, daily I get is "Hit 4 survivors with a Dash attack, using Pig". I don't play pig much at all but with killers there are mind-games and routes you can run on maps regardless of killer you play and just treat them as if you have no power. Queue time to enter game ranged from 10-13 minutes to get into a game. When I finally do get into a game, as a (currently) ranked 5 killer I am paired up against 2 rank 17s, 4 perks all level 1, and 2 rank 20s, 2 perks both level 1. Needless to say the game was not fair. I went out of my way to not tunnel or camp and still 4k with relative ease.
If you want to do an MMR system I would suggest leaving Killer MMR the same as Survivor and having it be an overall experience not on a per killer basis. It complicates dailies and enlarges queue times as well as push newer players away by pairing them up against someone that can have 1000+ hours (651 on PC, 1.9k on PS4). I know it's a rough transition this is just my feedback/suggestion in regards to the new MMR system.