I have been reading a bit, and it seems like it should be possible for two frost mages to take care of all the spawning adds - with a little help from a hunter with the boombots if needed.
I've done some testing and watched some spreadsheets and it seems like frost is "just" about 1k dps behind Fire or an arcane build.
So if you spec like http://www.wowhead.com/?talent#of0Vck0hZZAIcIRfu0c0gbox you should still have a close to viable dps spec, but also with a very nice slowing effect to blizzard - 90% to be exact!
What is your opinion on this ?