This topic has probably already been touched upon but just for the sake of contributing I'll raise it again.
Houses, especially the bigger ones, feel rather empty with no NPCs to populate them. We have the banker and merchant but those are just two, not much variety to choose from. Unless your house is the hall of a large guild, and has a lot to offer seeing as guild halls are a dime a dozen lately, your house won't be populated with players often. Feels anticlimactic for a large and well-furnished home to be so empty.
Including NPCs would contribute to the atmosphere of a house, even if they don't serve any particular purpose like the banker and merchant. Could be done by adding them as furnishings, like with the soul shriven you can purchase with crowns. I also recall a post suggesting the option to add our own characters as NPCs in our houses, which is also a great idea.