This is what I would like to see done with player housing.Well since you're asking.......
1. Choice of location. Give us a choice of different interesting and beautiful locations within each city/zone. By the beach, on the cliffs or even on an island in La Noscea! Canyon cliffside or by an oasis in Thanalan! Atop the trees or by a lake in the Black Shroud! The ideas are endless guys.
2. Interior and Exterior decoration. Obviously with a house comes customization. Please allow use to decorate the inside with various furniture, wallpapers and carpets as well as the outside with statues, fountains and exterior house customization.
3. Housing Expansion. Allow us to not only customize but expand our dwelling. Give us long quests and crazy requirements to get bigger and better houses over time. This makes not only getting the house an accomplishment but expanding it as well.
4. Allow other players to visit. What's the point of having a cool place of your own if no one else can see it? Allow us to bring anyone in our party with us to our houses. That would be the most simple way to do it while keeping restrictions in my opinion.