I think there should be more interesting use of this in Skyrim. Firstly, I think there should be more quests related to them. When a house does nothing but store items it seems a little pointless. It'd be much better if you could get more quests, or even a series of quests, like a mini faction, relating to the house you buy. I also think more variation in house style would be cool. Like if you wanted, you could get a house in a small cosy village in the mountains rather than a big city. Or if you are rich and famous, maybe even get a castle with lots of secrets to explore. And what if you could turn a house into an inn or something as a side business?
Just throwing a few ideas around. What do you think?