Here is my recount breakdown.
I was quite happy with how the spec held up from both threat and mitigation and barring any new changes to DK talents will stick with this as is.
Impurity really pumps up the damage Death and Decay does. The new Outbreak also allows Scourge Strike to hit really hard. My tank gear while very sound does not hit nearly as hard as my DPS set, and with the benefit of Outbreak my SS's were hitting very well.
Single target rotations are essentially IT, PS, BS, BS, SS and burn RP on UB, RS, then DC in that order of priority. If UB is up, and Rune Strike is available use it. If UB is up and RS is queued and you are still waiting on runes and have extra RP toss your DC's to maximize your threat. The second half of your rotation should be SS x 3. Assuming your glyph procced and refreshed your diseases keep using SS as much as possible. Use BS to convert your runes as required and maintain your RP priorities.
Multi target tanking remains similar to live. Start with DnD, IT, PS, Pest and dump RP into UB on the first pass. As your runes refresh focus on using SS. Use BB to convert runes and assuming you have the new pestilence glyph, use it just before your diseases drop off your primary target. Finally, maintain the same RP priority from single target. UB, RS, then DC.
For mitigation keep your Bone Shield up as much as possible. BS should be your third major glyph. Keep RP on hand for IBF and AMS as needed. If the magic is really coming in use empower rune weapon to cycle in AMZ. Lastly, save Lichborne for the final enrages. Increasing the bosses miss by 25% when he hits the hardest will allow your healers to keep you up at the end.