I'm inching towards the conclusion, and the end areas in Kingmaker are an order of magnitude more difficult than the endgames in any other RTwP RPG (or most RPGs for that matter). Fighting the numerous Wild Hunt mobs is already brutal enough, but the encounters that follow make me miss the days when my party was just a bunch of level 2s getting curb stomped by 3 Greater Enraged Owlbears with a Base Attack Bonus of 18.
Here's a mostly spoiler-free example:
The game hits the entire party with the following unavoidable debuff that cannot be removed through normal means:
Given the incredibly weak saving throws of your party, it then make you fight numerous enemies who spam "Save or Die" spells.
The only way I've made any progress is by burning through whatever wands, scrolls and summons I've hoarded so far, but oddly enough, I'm loving the absurd difficulty of it all.