Still in act one but it seems like difficulty is/was generally hard for direct combat. But you seem to be able to cheese a lot of it. For example I was fighting a 75 hp enemy in a room full of minor enemies, near impossible fight for our builds. Reload save push him into a pit, now fighting the remaining goons is doable.
Had that happen! The first time I decided to try out push, I had Karlach push a goblin into lava.
…I did not move her, because it did not occur to me that then she could be pushed into lava. Which is what happened the next round when an enemy dashed over and shoved her into a lava pit.