afk auto hunting is never going to go away so that should never be the complaint. maybe there is some universal vitality given daily so once you used up those vitality, you have less incentive to keep be in constant party so you can break away to explore the world and do things.
but make the vitality worth it on a daily basis... up to you game designer to make vitality 4 hours, 8 hours per day whatever you think it's a good balance. outside of those 4 or 8 hours, the XP reward drastically drops forcing people to do other things instead of mindless senseless XP XP XP. lol.