well heres what i came up with for vampires.....require to feed for they dont age but when they do feed they get huge bonuses in everything but its really easy for them to be caught due to highly populated areas. for werewolves they shouldnt be able to get the well rested perk. they also should only be able to transform at night when its a full moon and it should require you to feast on so many people or animals otherwise you get very weak and will die rather easily. this system should also affect npc's