An expansion where we are the ruler of a starting town, which we can expand and grow in wealth. By controlling resource gains and resource deployment/dividing, controlling the people on what to do and what to become, drive trade with other towns, expand the town itself, research upgrades, and build up the town in every way possible(political/wealth/size). Bit of a strategy & resource management & political side to ESO. This could even expand to already existing towns and zones, to do trade with those or gather resources from those zones. Maybe even add a reputation system with this: a town likes you more and you gain bonusses there, another towns dislikes you somewhat and everything is more expensive there. (just examples)
Not sure if something like this would be solo player possible, or would have to be communitywide for this to work. Afterall we couldn't all build and maintain the same town in seperate instances, could we?
Personally I would love something like this, but I am not sure if this would fit ESO. So I figured I would post it and see what others think.
PS: Maybe tradeskill hirelings could become a part of this town, instead of being e-mails.
PPS: This idea is not taken from another game, though it possibly may exist elsewhere already!