On keys without an affix the timer should depend on the average groups ilvl so that people gearing up on a low ilvl don't get discriminated on. This also would hurt carry groups which is bad for the game because it forces people to just go get their key carried instead of interacting with other players on the same "level" as them people around the same ilvl should want to play together and do content that will be challenging for them equally.
The way the game is now if you are a DPS under 870 ilvl goodluck getting into anything.