Speaking of horrible tanking experiences tried a Tol Dagon this week with Tyranical + Necrotic and I felt powerless verse that first boss. The boss has periods where it would clear but I would always get clipped by one add fucking me. Granted I have only ran that zone twice so my experience there is limited but goddamn did it feel like untested shit design.
Don't agro the adds let the dps tank and kill them they die pretty fast if all dps swap to them, as a healer I normally get agro on them by default I just move around and keep them on me while the dps kill them also yo can clear a few extra packs give people more room including the tank to kit and clear necotic. But i agree if the dps don't kill the adds fast enough then nothing tank or healer can do you going to wipe over and over, it is another prime example of a post I made earlier about m+ now requiring the whole group to be decent at mechincs not just tank and healer doing all the tactical stuff correctly and dps just making big numbers.
I done the place with a druid tank at +10 was pretty easy i was execting it to be hard with a druid tank but dps was spot on for first boss adds died super quick and tank never had more then 10 stack of necrotic, I also done it was a VDH tank at +7 we called it a day after 5 wipes meter showed 2 dps doing zero or minmal damage to the adds (I done more as MW) tank would get 40 necrotic in next to no time