The hunt solution: scaling HP (used in GW2 and WoW already...)

[LunaHoshino]

Also, it's far easier to grief people right now by pulling ASAP and then laughing at people who didn't make it in time.

It's not griefing if there are enough people there to kill the mark. Why should those people stand around waiting for an indefinite number of other people? They're playing the way the content was intended, which was that the players who found the hunt have the right to decide when they're going to pull it.