reserved for answering questions
In this video we went warrior with SW LS fully glyphed and talented, then myself with barkskin SI, then the warrior's cooldowns were back up and he took the 3rd. There was no 4th and I very foolishly hit SI at the end of the cast instead of the beginning. Had i used it as soon as he started casting the second big bang it would have been up for the 4th.
Our DK uses 4pc AMS and IBF both of which had a shorter cooldown than the 90 second big bang. Unbreakable armor and Vamp blood can be used by the DK on the boss as neither is needed for him to survive big bang. I do not raid with a paladin tank so I am not sure how much health they survive with when they use divine protection sorry but it should be enough.
A DK can take every single big bang, they are the only one of the 4 tanks who can do that without external cooldowns
As for dispersion we have our shadow priest on stars in 10 man so threat is not an issue when he does it. The warrior or myself simply taunts back and he goes back to stars.