I'm not intending to spark a discussion here (though I might end up doing just that anyway, such is the way of things), but as a ... warning? I guess that's the right word. For my part, I'll be containing my opinion on the matter to various discussion threads on the forums.
Blue posters are assuring people that the changes will NOT be retroactive, and that there'll be ample warning provided that you're letting people see your real first and last names on posts once the changes go into effect. And also that blue posters, Blizzard employees, will be subject to the same process.
Official Announcement: http://forums.worldofwarcraft.com/thread.html?topicId=25712374700&sid=1
WoW Insider Article: http://www.wow.com/2010/07/06/official-forum-changes-real-life-names-to-be-displayed/