Any elite mob in Gazluk Keep can potentially one hit kill you ( while you are wearing lvl 70 legendary armor from this dungeon, that has been transmuted / augmented/ and possibly infused) besides tacticians( and possibly mages / mutterers..don't quote me on that part), if you are not specifically using one of the 4 or 5 tank builds that are extremely focused. Even an instant kill from 80% health and armor is kind of unacceptable, 50%? maybe. I would imagine that almost any elite mob in any dungeon will do the same thing to a person who is actually geared 'at level" for the content. If you have the tools to give yourself something like 500hp regen per tick, you could easily test this by wearing level appropriate gear and stand there waiting for a rage attack to critical on you, and see if you survive, this assumes you also have level appropriate armor and health of course. And by level appropriate I mean 1 tier of gear below what drops in the dungeon you test it in..as in, you are a regular person running it for your gear...of course in gazluk keep itself you can wear whatever you want as long as it's normal shit available to players and you will still die, but keep in mind that a lot of people are there to GET level 70 gear.
The non-elite mobs on rahu plateau... not the debilitators and not the ones wearing heavy plate mail..I want to say Onkara super soldiers? can one hit kill a person with 935 armor / 600 health, their rage attack may be bypassing armor however, also there is something strange going on with the debilitators in the same area. I notice them hitting me for like, 30 health and armor, and doing a small DOT ( 9 damage or so) and a few seconds later I'm suddenly dying so fast i can't really tell what's killing me.
I'm also pretty sure General Prask hit me for 1600 damage today with those same stats with a rage critical. However much it was I was literally at 100% health( 600) and armor ( 935) when it happened, I know this because during the fight with him I became bugged with the bard bug and had insane regeneration( not intentionally, incidentally I have reported this bug and sent the output_txt thing to PG's email a few days ago).
This is about the best I can do now since we don't have a combat log to go over what is happening and give you real specifics, you have to understand.