The PC/Mac people already have this, but it would be great to have on console, the ability to save equipment/skill load-outs and call them through the quick slot. Maybe give everyone 2 load-outs (you could save your current load-out to one of the two, change things up, and save to the other) and then offer additional load-outs at 1000 crowns. Win-win, ESO gets money and players get more functionality out of the game.
Another easy money maker for ESO, how about style add-ons for mounts. Just as we have these with our characters, certain styles could apply to all mounts, or specific ones; like horses, guar, wolves, etc.