I think SE buffed the mobs in the HW dungeons, certainly the level 60 ones. I think SE did that to dissuade people from doing speedruns. As a DRK in full law with 15k HP, I get absolutely wrecked if I pull more than 2 groups (and even then 2 groups is too much. Might be more possible to do speedruns in HW dungeons in full Eso sets, but in Law, it's better to just pull one group at a time.

BTW, any tank worth their salt will let the stupid DPS die if they pull mobs trying to hurry the group up. Tanks and to a lesser extent healers, choose the pace, not the DPS. You wanna control the pace, then be a tank/healer.