Another advantage of frost is that you can use hungering cold to interrupt if everything is on cd and the mob isn't immune. You can even interrupt multiple targets if they're in range.

With the glyph it's zero RP cost.

Versus a non-boss target (such as a player), a Frost DK can pull off a hilariously large number of interrupts in a row:

Mage: Frostbolt.
DK: Mind Freeze!
Mage: Frostbolt.
DK: Strangulate!
Mage: Frostbolt.
DK: Death Grip!
Mage: Frostbolt
DK: Hungering Cold!
Mage: AAAAARRRRGH!!!!!

An Unholy DK can substitute Ghoul-stun for Hungering Cold I suppose.

I'm currently specc'd into Endless Winter and Hand of Doom, and find both very useful in the current heroic environment (and even in 10m raids, when sometimes we don't have all the interrupts we'd like.)

Mage: Run around in circles and spam Ice Lance and instant freezes.
DK: Dead

However, that combo is very nice on pve mobs, so don't let it dissuade you, especially because you should be able to get another mind freeze into that rotation :)

And hey, whatever makes you happy, because we're all better off with more interrupts than less.

Endless Winter is marvelous. No need to monitor RP waiting for critical interrupts makes everything easier. I've taken to competing with my pal the enhance shammy to see who can get the most interrupts in heroics (curse his shorter CD!!).

Hungering Cold as an AOE trash interrupt is also epic fun. And I love the glyphed version to death. Again, no need to monitor RP makes the it hugely versatile.

Stella,

You are posting this same rant over and over again on every thread.

For the love of the Light, join a guild and stop crying about how LFD ruined the "community". Nobody is forcing you to use LFD; you are free to only run content with your personal friends from your server. It is not up to Blizzard to provide you with a "community" that is to your liking; it's up to you to cultivate one by forming relationships with people that you want to play with.

Furthermore, your description of LFD dungeons would have been total hyperbole back in the late-Wrath Go Guy heyday and bears little to no resemblance to anyone else's LFD Cataclysm experience. Nobody is facerolling Cataclysm heroics without group co-oordination, including the use of CC and interrupts. Maybe later on in the expansion, highly-geared groups will be able to do this again, but it's not happening now.

Finally, every damage meter out there already tracks interrupts and CC breaks. And "battlegroups" were done away with months ago. Your rant makes me wonder exactly what you're basing it on, because it's not the current state of the game.

@Stella--

It's true that RDF is often painful at the highest levels. But it's better than what was before. I can actually -run- lower level dungeons, for one, and about 90% of the low level groups I get are good, friendly runs. Occasionally you get ninjas or tanks who think healers can heal with no mana or someone who's clueless (melee hunter!) or people who forget what it was like to be a new player, but most of them are fine. For another, back before RDF, in the ToC era, it was nearly impossible to find a group for a heroic that wasn't the daily quest, much less normal modes. Once the dungeons are simple enough to pug, RDF works.

Cata heroics aren't what RDF was made to do.

But the solution is simple: once you hit Cata content, pug in trade on your server. There are enough high 80s to support this, and a 3/5 majority will give you majority in case you pull someone intolerable. Problem solved.