I dont see any difference we are in act 2 now whit my wife karmic on just to see the difference. I feel is like setting the frame on a fixed 30fps. So generally I feelt I am more stable balanced. We hit average 60-70% but eventually we will owercome this at act 3.
But enemys still cannot hit us . They trie to hit my wife all the time and she have 27-31 armor class while immune to critical and she have the shild spell as reaction mostly it don't even want to trigger.
So for you questions answe carmic dice on or off doesn't increase the difficulty.

The monsters are still dumb and I noticed that some monsters enemys are not effected by the tactican hp increase at all.
After act 1 some enemys have lower hp then in act 1 even bosses. For example act 1 optional boss have 400 hp act two main boss have 200 hp. And the lvl difference is huge.