Gave a shot myself last night. Got charged for 1800 and non-crit hit by mortal strike for 3890 and instadied after like the 15th attempt. Apparently it's a shitty fix where he's scripted to reset if you stand on the ledge as I managed to kite him way farther when I was off the ledge (that's the part where I died).
Even if it will never be soloable they should normalize the guys damage. My guild did a trib run (regular one) and our full t1 tank got 1shot in the same scenario after he pulled and they all wiped.
Look at this retail video:
https://youtu.be/dXE_RR5XzE8?t=14m45sA hunter is being hit for 400 and survives gordok for a long while. Tanks with full gear getting 1shot in a dungeon, while they can tank Ragnaros longer. What a joke.