It isn't necessarily the fault of the mob's HP pool that it dies so fast. It's relative to the high volume of players who have jumped back into hunting. Prior to the World of Darkness patch, hunts were very casual and only became really busy when it came to S Ranks. Since there are new shinies available to both non-raiding players and already raiding players, everyone is now seeking those hunts for their next Carbontwine or Carboncoat.

Once everyone gets their items again, fewer people will start hunting again, and the HP pools they currently have will make the feel beyond bulky.

Also (correct me if I'm wrong), I do believe hunts scale based of off the amount of players nearby it, correct? Just like how Fates work... I think. *scratches head*