Wishmaster
Greenhorn
The basic idea I have in my head is that you have the option to set a nickname while creating your character and once you reach a certain number of hearts with a villager, they might ask to use the nickname (similar to when your spouse asks for a child) and if you say yes, they will begin to call you by that nickname. This could extend to your spouse/partner too, you could have a nickname that only your spouse uses. Just an idea, might be a little out there