I'm a 93 Warlock and I literally JUST killed Shaper of Flesh.
I had to go in about 10 times, thankfuly he doesn't regain health when you die...
I have a shit ton of damage, damage immunity and crowd control (freeze nova). My resists are maxed and I have 7k health and like 6 auras and I still get 1-shot by some Behemoths and Titans here and there.
Game is somewhat unbalanced IMO, in the way that nobody could ever complete this game on hardcore or if they did, killing a boss would take them an hour?