Many players view their time commitment to a game as an investment, even if they never intend to cash in on it. Hands up who here still has an Ultima Online account tucked away, or an Everquest character gathering dust? So making drastic changes to a running game world is a thorny proposition for development teams to grasp. Even when making the most minor of changes, if players perceive any aspect of their character has been weakened -- or, in other words, their investment devalued -- negative publicity quickly follows.

Of course, this happens anyway with every patch known to mankind. The choice of whether to nerf regularly or resign the game to an ever-increasing arms race of superiority isn't exactly tough. But the rule of thumb for most MMOs is to make small changes, and gradually.