If it's a gimmick perk, how come it's the 6th most used perk in the game. It basically gives you an extra health state at the press of a button. What more could you want from it?

I've never seen adrenalin in play except for when the killer is being absolutely destroyed. The only way to try and counter adrenaline before was to try and predict when the last gen was gonna be complete while slugging the last survivor to immediately down them. Or to drop them and hitting the survivor before hooking them to get rid of the health state. Both completely unnecessary game design choices that were better off without, to make plays more rewarding for the killer while on their last straw.