If you havent yet seen:
http://www.mmorpg.com/gamelist.cfm/game/821/feature/10506/Elder-Scrolls-Online-More-on-the-Thieves-Guild-DLC-with-Rich-Lambert.html
MMORPG: What sorts of updates will we see to Cyrodiil with this DLC?
RL: We’re hard at work on improving the overall performance in Cyrodiil so there are a number of behind the scenes server and data performance improvements going in. In addition to the performance improvements, there’s a new non-champion point campaign as well as a new traveling vendor who you will be able to purchase monster mask sets from with AP or Gold (dungeon sets).
MMORPG: What are the benefits we'll see with a 64-Bit client?
RL: Players will see some pretty significant stability improvements (i.e. – less crashing or stuttering) as well as overall performance improvements as the 64-bit client will be able to take advantage of larger memory pools.