I agree with Jwilliams and Gerolan. More HP so they at least take a few minutes to kill with a big group attacking them and giving people different weekly hunts to stop such huge gatherings trying to hunt the same mark.

Could maybe keep everyone having the same mark if the HP was adjusted high enough, something like behemoth HP on the first or second stage would give people enough time to get to it and get some hits in. I've been stood next to Naul twice unclaimed with a group, attacked it from the start and still didn't get credit for the kill...