Gen speed / Healing speed
I see a lot of people saying gens should take longer to repair, but I don't agree. Pressing m1 is the most boring part of the game, and it already takes too long in some matches. Many times killers aren't being able to keep up with that because of underwhelming killer powers and map design (very strong connecting tiles, huge maps, difficult trackability) which is a problem that should be addressed.
That being said, gen speed is a problem if a team brings very strong toolboxes, resilience, prove thyself, etc. There should be a cap to individual and combined effiency in repair speed. That should also apply to healing. This should be a great start in balancing the current feeling of gen rushing, and putting CoH and strong med-kits in a more reasonable level.