I will caveat this post with the fact that I'm not yet at the level to hunt, but have been in the vicinity and seen how stressed people get over them.

The issue I see is that the risk/reward is off. I would change them as follows:

1. Virtually always up somewhere in their area
2. Lockout - 1 day for B, 2 for A and 3 for S
3. Cap token rewards per week
4. Lock the mob to the party/person that pulled, maximum 8. It would turn green to everyone else. If the party wipes, the mob walks off and vanishes (as it will probably have spawned elsewhere)

By keeping mobs up virtually all the time it will mean that somewhere, somehow, players can find their mobs, and if they stumble across one which has just been pulled there's no incentive to grief as they couldn't hurt it even if the group wipes.

This would require group play and would still keep some super strong mobs just strolling in open world.