This is my favorate fight this expansion as it lets healers get really creative how to heal the boss. I am sure healers heal (and hence damage) the boss more than dps.
That 1.2 million heal tick from execution in the above log is nice.
I think swapping Beacon to the boss can also be amazing this fight if pallys eternal flame the raid just before the sun breath so all those healing ticks heal the boss for 500% more.
Any class that can heal eg. ret pally, shadow priest, ele shamy, druid get the breath and heal the boss for those 6 seconds. That healing is 5 times more than any dps you can do.