A lot of people are missing one of the side benefits of shirk: it's not just for tank swaps! I was doing deltascape 2.0 last night with a tank friend of mine. After a minute or two into the fight (so there was a bit of a enmity lead) I would, as the OT (READ: spare dps in this fight) provoke the boss and instantly shirk back onto the MT, essentially giving him +25% of his current enmity. From then on I repeated that every time it was off CD, which meant the DRK never had to use a enmity combo after that, even with good dps that were pushing the meter earlier in the fight.

As already stated it makes tank swaps so much more comfortable as well, you don't really need to be careful after a swap and the new tank only needs to use at most 1 enmity combo at the swap.