What about Twins and Oni, Myers or perks like Haunted Grounds?
Have you really thought this true?
Did you even consider high level play were Onis actually have game sense and use his power to down multiple survivors (the only thing that really makes him strong) and not just use his power to down one surv?
Have you thought about the Twins, who basically have to slug with Viktor (20 sec with Unbreakable isn't enough to go with Charlotte to the other end of the map)? Besides that, snowballing with Viktor is an essentiall strategy and and does make them strong. Survs had to be organized, now they can just abuse mechanics.
What about other 1-hit killers like Myers or Ghostface who can only use their power for a period of time and therefore slug?
What about perks like Haunted Grounds which only make sense to bring with you, if you go for multiple survivors?