Player housing?
It would be awesome, and I have a strong feeling that the GH mechanics are some sort of pilot project for a future implementation of housing.
We already have the home instance! Perhaps a chance of fully customize it, it would be amazing. For example, in Salma district, you being able to actually buy more than one house (not the story-linked ones though) and do a makeover there, even changing the blueprints!
I can only dream. Wildstar got this feature and is pretty robust there, basically one of the best parts of that game, in wich you can lose months just doing that (obviously, taking into account that you have gold for it).