1900+ on Karagga is impressive, particularly in light of the fact that your main spec is tank. I've seen people get higher, but it's not common. As for Fabricatorů Everyone gets insane numbers on that fight due to the damage boost. Your DPS there is much more a function of the speed of your puzzle solvers and the strategy you're using.
I'm a fan personally of the "stand him on one spot and cause everyones game to crash due to absurd numbers of exploding probes spawning while constantly setting him on fire becuase you've 3 people unstairs and oh god everyones character model disapeared becuase there's so many probes **** WHERE'D THE BOSS GO!?" tactic.