I'm glad you agree with me
Sentinel Marauder advice
Get a tank that moves the boss around the edge of the room. you cannot keep him still if you have melee in the mix. there isn't enough time to get the balls far enough away. stay behind him and help interrupt incinerate.
The funny thing only 2 times when I did kill the boss tank didn't do that.
And when other tanks kited him, we wiped faster