See I don't agree with half of that. You're not increasing difficulty, you are hamstringing yourself and limiting game play options.
Not to mention increasing the way CC works affects both groups, both you and the enemies. So that to me is a non factor and honestly works more to weaken them than you.
Honestly its AI or bust..numbers are just numbers, if all you want is numbers then go download Rhidian's mod..higher heal cooldowns, -100 resistance to start game to all elements, all enemies have a boost to vitality, willpower and bodybuilding, summons are interesting because he added utility skills ot them to fit their element but with a super high cooldown.
I saw a couple people saying asking for AI is like asking for the moon, but let the modders get their hands on the nuts and bolts of the AI. Reconfigure it, BG2 was not NEARLY as punishing until people got their hands on it. Then all the sudden enemies started casting new spells, using their potions and wrecking you..