Already there are multiple classes/specs that complain alot about Raid spots. (most raids bring only 1 maybe 2 mages, ret pallys, prot pallys, elem shammys, DPS warriors, feral druids, boomkins).
I'm at BT and we never bring feral druids (cat form ), ret pallies and DPS warriors havn't had one in raid since kara. These specs barley ever make it in as it is now. If they choose to play that spec thats there take on WoW. I wouldn't play any of these specs now that i know as much as i do about the game. DK will just make the raid better and guilds will cut off the next weakest class.