I don't think I have to spew out credentials, but trust me when I say that I have extensively tested all the viable raiding specs as of 3.1 and 6xanything is not the way to go. True, it will be nice for the very undergeared as your spells aren't as dependent on your gear as most blood/unholy specs are. But "FS can't me blocked/Parrier/Dodged which makes it perfect for non-hit capped DK's." Frost Strike can still miss, it's just immune to expertise caps. Along with that and the fact that you're casting 6 Icy Touch, 6 global cooldowns are dependant on the spell hit cap (17%). That makes this 6xIT Machine Gun Spec the MOST dependant on hit rating.
As far as keeping up in raids, you will beat other DK's and players in greens, but once you become geared in even 10 man naxx epics, a normal frost rotation would beat this one, or even moreso a blood or unholy spec. Frost atm is too nerfed to keep up with the other 2 trees, and if you wanted to top meters, you're best either going 51/0/20 or 0/10/61.