From the difficulty I have to say that the 2nd run on higher difficulty felt much easier because I used more effective class/subclass combinations. Might be worth to balance the class/subclass skills a bit more (trickery domain, wild magic etc are quite weak)
My own experience has been the opposite, I find my 2nd play through to be MUCH harder. The reason for this though I feel is my active effort to truly RP the character and not min/maxing for game mechanics. I am playing this run as a Paladin in the traditional sense. This means a bunch of the companions are not around. Also means I can usually not talk my way through fights because my Paladin does not lie. The result is I find myself in more confrontations since I cannot avoid fighting evil by bluffing my way around it.
