I just don't understand the reasoning behind it. If it's to clean up the forums by adding accountability to it, then surely there are other steps that can be taken (similar to this forum!) before going to the extreme of forcing people to use their name.
If their idea is that this is step one of creating some sort of social networking thing, then I suggest they stick to their core business of creating and support great games. How about instead of wasting resources on this, put them into releasing an expansion for WoW more than once every 2 years?