It's a minor detail, but how about when the barber cuts your hair, it changes? It can grow over time too. A couple of other suggestions:
- More things like the Dragonblade, such as a lizard eye or something which could be used/given to various character (witch, Georgie, etc.)
- Castle interior/town exterior upgrades which can boost certain stats or bring them down (such as ugly decorations or a golden statue, which can have a chance of being stolen and other chain reactions)