I never have an interest in playing on anything higher than normal. And in specific cases of encounters, I have no ego invested in not lowering it down if necessary. And, I also use some of those optional toggles. I always turn off enemies critting you, for example, because if I do suffer one of those one-shot kills in my party I'm going to reload the game anyway, so why go through that hassle?
In Km on normal difficulty, with no mods or cheating of any kind, I've been able to get Valerie's AC to over 50, along with very strong saves. So I can just send her in alone, get the nastiest enemies to mob her, and then go in with the rest of my party and clean up.
KM is easier as enemies mainly just focus the first tank they see. in Wrath, they target the squishies. I'm not quite sure if is a difficulty thing. The minimum difficulty i play is Core. Which is still quite easy compare to Hard.