...[today's] virtual worlds are not as sophisticated. Yes, they have the 3D graphics, but what you can do in them as a player isn't as sophisticated as what you can do in a textual world. This means players don't have as many tools and abilities available to them within the world to enhance the experience of others.
And of World of Warcraft, Bartle says:
...I'd close it. I just want better virtual worlds. Sacrificing one of the best so its players have to seek out alternatives would be a sure-fire way to ensure that unknown gems got the chance they deserved, and that new games were developed to push back the boundaries.