One thing I'd love to see ESO bring on are guild halls. Guilds can pay X amount of gold to have a permanent establishment in a town. Due to limitations on physical area, all guild halls could be a single structure with the option to select which guild you wanted to go in upon attempting to enter. Guilds would have the option to allow guests inside, but by default it would be members only.
Inside the guild hall could also be a permanent merchant that sells items for the guild, eliminating the need to buy into the weekly kiosks. Since the kiosk were intended to be a social way for players to experience item sales, this would also promote that, except it's less temporary. By having players interact with other guilds, more than just wayshrining to each and every location looking for what they want, players could actually get to know guilds and maybe get recruited.
This could also help promote guild interactions with the public (RP nights, auctions, raffles, etc). Again, it's really hard to learn more about a guild without becoming involved with the guild as a member. Sure, there are tabards, but to have an actual guild presence in this game is only with recruiting, zone chats, and third-party word of mouth.