Not saying a DK will rock, or won't rock...
But if being CC'd is your issue.

Frost DK has:
- Trinket, every 2 minutes.
- Lichborne, 10 seconds of cannot be feared every 2 minutes.
- Icebound Fortitude, 12 seconds of immunity to Stun every 3 minutes.
- Pillar of Frost, 20 seconds of knockback immunity every minute (of glyph it and macro... /use Pillar of Frost ... /cancelaura Pillar of Frost, to act as another pvp trinket).
- Desecrated Ground, 8 seconds of CC immunity every 2 minutes.

Between: Lichborne, Icebound Fortitude, Pillar of Frost and Anti-Magic Shell, you have a window to deliver your burst.
You can also Desecrated Ground for another small window of immunity to CC.
And Trinket too.
If you want, you can remove Pillar of Frost from the initial set and go with the macro to cancelaura which then means you have a 1 minute ability that functions as a trinket.