There is an interesting phenomenon with PCs and the Internet. A jpeg of some very colorful and vibrant venue can be posted for general viewing. The poster will see it as bright and vibrant, and some unknown number of others, but not everyone. Move that into the environment of a fast action video game. If there are a consistent number of players reporting that from their combination of hardware components called a PC, they can barely see what you think is fine. You have a problem, especially if nothing is done about it. Now you have a real question of player ability versus hardware making the game easier for some in the minds of subscribers already impacted by the new game engine. I think we were beginning to see something like that during the open beta one could postulate. Now what is too bright for you, appears to be just about right for those who couldn't see anything during normal game play.
You could always turn your gamma down.......