@izecson Both. Both is good :D
@DaWaterRat I wouldn't mind having them have abilities like full werewolf shift, enhanced hearing, ability to turn another Sim, resistance to the moon cycle etc on a skill tree, but it would indeed take some creativity to develop an entire collection the way spellcasters and vampires have. That said, I'd really not like to have them reduced to just "oh hey, I can turn into this one shape and bite other Sims". It could potentially be done via a Werewolf (or Shifter) skill rather than a full abilities system.
