Are WD's that different? I can facetank T2 with my Wizard and he has 245k health.
That's really low for him too, but a wiz can survive more hits than WD.
I have my pets running around and I'm good...unless I run into orbit/frozen mobs. Even with 1800+ AR, I don't feel that I have the survivability in T2 -- oh, I kill things well enough, but surviving unique mobs with the formentioned affixes is difficult.
Hence my comment about low health.