I despise barrier servitors
Barrier champions are a cool concept. A bit strong (supers should pen barrier shields IMO), but a cool concept. A tough enemy you have to kill for maximum points, but require you to dedicate firepower to them for an extended period, in which time the adds will kill you. Fail to kill them, and they regenerate all their health. So you ad clear, then focus them down. Cool. Makes sense.
...
So who the FUCK thought it was a good idea to make a barrier champion that makes all the adds immortal? It's mildly infuriating.
The worst part is that they're not difficult. You can kill them by sitting a mile away, waiting for ads to trickle in, and go 'plink plink plink' until the room is clear. It's not hard, it's just annoying. Which, IMO, is the worst thing a boss/miniboss can be.