I think for hard max should be lower than 72, if people want the "everyone Dino" strategy, it won't fix the problem of not being able to claim (too low % damage unless you got first claim) and SMN/SCH dots not staying at all (it's more critical on SMN since Fester depends on it).
That or they have to make it so its more attractive to not stack with 9 parties.
They could make it so HP scales with the amount of people who cleared mobs nearby last, like FATEs. This would discourage heavy stacking since mobs wouldn't die that faster. Then people might go for other hunting spots, eventually getting an equilibrium of 2-3 groups per spot, rather than all 9 in the same.