Will “phasing” be used more extensively in World of Warcraft: Cataclysm?
Yes. We’ve come up with a number of new, cool ways to use phasing since we introduced it in Wrath of the Lich King, and we plan to use it more extensively to change the world as players progress. We are also now able to phase terrain, which players will see firsthand in the starting areas for the goblins and worgen. We’re also adding some UI improvements to help determine when another player is in a different “phase” from you.