I would love to see a large story-related quest system, similar to WoW. It is already possible to solo all the way through this game via leves (in fact, I can do so faster than leveling in a party), and I doubt they will revert to the leveling system in XI. Most people don't have that kind of time to dedicate in one sitting. This is perhaps the biggest thing I find lacking in the game, and I really do hope they are able to work on it.