This is a terrible idea. People will just claim the mob instantly and try to hold it while their party gets there. It will make every single aspect of the hunt worse than it currently is. Plus it introduces even more class-ism to the hunts. Pretty much just jobs that can solo or live long enough for their party to get there will benefit from this idea.

Unless you pretend the mobs to disappear mid-fight, to which I just say: Lol.