I would love a Victorian London type world with cramped and narrow alleys, rows of townhouses (apartments) stacked claustrophobically close, lamps that cast a sickly green glow over the streets, an "exotically" decorated low-brow lounge resembling an opium den, and a dirty Thames river with a bridge that leads to the haunted forest. There is a grand, haunted cathedral in town, and an "abandoned" mausoleum and graveyard in the forest.
A "Jekyll and Hyde" as well as a "Picture of Dorian Grey" type of atmosphere would fit perfectly with werewolves to me. Build/buy mode could include Gothic themes for the spooky cathedrals, and East Asian themes in teal, red, silver, pearl etc. since imported "exotic" items from East Asia were often status symbols of the upper class - I feel that these items lend a very particular atmosphere to this setting that is very fitting.
This world itself would already be a great treat to me, but extra gameplay could include:
- The Chinese boardgames Go/Wei Qi and Mahjong.
- A special herb-infused tea that makes sims dazed/scared/hallucinate and sometimes convinced that they saw a werewolf.
- Expanded kleptomania trait: pick-pockets are rife in this world.
- Jewelry-making and blacksmithery: create jewelry, little sculptures etc. from metals and jewels, especially silver.
- Burrying items under exposed soil/sand (creates small heap), ex. time capsules, valuable items etc.
- Two collections: "holy relics" and "unholy relics" that can be found across the world. Similarly to Jungle Adventure relics, they have different magics attached to them and either attract or deter the supernatural.
- Chains and shackle item and dungeon gates: meant to keep werewolves contained when full moon arrives, but can also be used for general evil-doing in the basement.
- Therapy booth: reminiscent of a confession stand, let your sim spill their dark secrets for some temporary relief of negative emotions.
- Free update: graveyards and funerals.
Integration with other packs could include:
- Moonlight affects magic and potions in Realm of Magic.
- Dogs from Cats and Dogs howl at the moon.
- Moonlight affects mermaids in Island Living (tide magic etc).
- Special interactions with vampires and spellcasters. A special type of spell and/or potion that affects each supernatural (ex. bone digged up by werewolf infusion makes spellcaster more powerful during full moon but gives vampires an intense need to be underground, ex. in a basement). An alliance between different types of supernaturals can create a pack or coven with more diverse powers, or a war between supernatural packs and covens strengthens the powers specific to each supernatural species.