Storage, enough said.
A market or AH NPC. For each house or district. Tie it in like current AH systems work. You own a house everyone that owns that house has the same NPC access. This would give people incentive to own more houses/properties so they could have access to more markets, and it would also give access to selling items (which now include housing decorations) to other people more easily. Or you could make it tie into a racial vendor. So if you own a Breton property its a Breton vendor that everyone who owns a Breton property can see and use.
While I am the first to say that SWG is maybe the most over rated game in history because people use it as the white whale of games that were the greatest ever and nostalgia clouds their minds, it still gave players the ability to sell from their homes. Something still unique (AFAIK) that no other housing in any other game allows. ESO seems like the perfect opportunity to bring that back in some way.
Crafting. An other obvious one. The excuse most games give is crafting in towns brings people together and makes the game looked alive. But with phasing and the spread out nature of this game world that really isnt the case. I dont see dozens of people surrounding crafting stations shooting the breeze. Or even certain towns over loaded with people there just to craft or even do writs. So that excuse in this game doesnt work.
Crafting stations in houses adds to the look and feel of the designs people will do, anything with a courtyard or cellar makes it obvious.
Overall I found this whole housing update rather underwhelming. While most people think the prices are OK, they wont once the see how much it costs to decorate them(even with the tiny limit caps, which are tinier without a sub), then the whole DLC wall for some of them. Cant buy them (at least with in game currency) without the DLC content. So it sort of makes the whole 'free for everyone' dubious in some aspects.
It adds a whole new mechanic to the game and one that many many many MMO players these days all feel is a must, therefore it should be an earth shattering groundbreaking change to the game. I am sorry but this one just doesnt come close to doing that.
Its great for people who already play the game and are fans already. But I just dont see it offering anywhere near the immersion and "RP" factor necessary to bring new players in or make old players return. It just doesnt have enough meat to it. Pretty instances and little else inst going to mesmerize people into flocking back to the game.
You need a system that is a time sink (without a grind) and one that lets players access things in other ways besides the way they are now. And in a way that doesnt break immersion. Those big three things I mentioned above (and there are more obviously) can easily accomplish and fulfill those criteria. I would dare say theyre almost needed to make this update something that isnt a one hit wonder (Like Lotro housing was) where people bought a house decorated it and never wen back. And Lotro housing even had storage.
Bottom line is housing in a game like this has to be more than what this offering does.