In Oblivion I really enjoyed collecting artifacts and unique items, so it kinda annoyed me that there were limited display cases in the housing in Oblivion. Something that would be really awesome is customizable (to some extent) homes. For example you can buy an Imperial Shack sized house that is located on the outskirts of a city (with its own map marker, another thing that annoyed me in Oblivion, but it was understandable). You could then go to a renovator/furniture shop and upgrade it by buying more rooms and furnishings. The rooms would have a preset size but you could choose where the furniture is placed.
Another idea I had was that various wealthy families would own forts and such and you could hire mercenaries or private soldiers to attack other people's properties. You would also have to hire guards to protect your own property, and this could also be another thing the new quest system could work with. Maybe if your home is attacked a messenger spawns near you so you have a chance to defend your home.
So? Good ideas? Bad? I know its probably too late to implicate, but if they already though of this it would be awesome. Also I'm console so no mods