I just finished this game on torment level with a created by myself party and i feel a bit weird about the difficulty and game design.
First chapter is crazy hard - one shooted is a common state. Took me ages to went through it. first 5 levels is actually a torment.
Chapter 2 is easier but still i was not able to reach some areas.
Chapter 3 is a cakewalk.
When u go out to normal world ( or rather teleported) the game starts to be open world and ....become disappointing easy.
I was playing with 2 pure mages, pure priest and mele/priest.
Second problem which i see every mob has 90 % physical damage reduction what is a big lol and afterall i used mele/priest only to heal/buff and where there was no need for those the best choice was to skip a turn - this is a big lol. Normal mages summons are more usefull then your main mele characters......
so my idea is that the game should be a bit redesigned: low levels areas should be easier and higher levels more tricky ( or however to put it)