How I would fix Plague
Plague was the first killer I played and ended up being my favorite killer when I bought the game. (around when ghost face came out). Before dedicated servers I remember being able to charge your vial purge/ corrupt to any amount. But now if you try to release your puke before 25% you cancel it and get the cool down as if you used it. I would revert this change so you can charge and release at any amount.
Besides that change the only other thing would be her bug with hitting survivors with vial/ corrupt purge and the survivor yelling & going through the animation of being hit but nothing happening. This happens multiple times a game and it's very frustrating when it happens at crucial moments. This bug is why I find myself playing her less and less.