Mark Jacobs knows the problem with your games: They're too predictable. What MMOs need are some good old-fashioned chaos. What happened to the days when you would turn in a quest for which the reward could be endgame armor or it could be a piece of moldy cheese? Let's bring that back into style!
All right, not that far. The latest Camelot Unchained development blog is all about randomness, however, with Jacobs laying out another design principle centering around the need for a strong random element in play. Jacobs sees a need for unpredictable outcomes as one of the core elements of a game, something to keep you playing because the game cannot be expected to run a specific course every time.
This extends to both the combat system and the state of the world in general, with the former embracing more factors than simple levels and the latter being a bit more dynamic and unpredictable. If you're interested in reading more on this point, take a look at the full rundown at the official site.