I still feel like the only D&D-style CRPG that really hit home for me has been Temple of Elemental Evil. It needs extensive modding to work because Troika didn't know how to make video games, but it's so damn good. Kingmaker lost my interest a few hours in, where I felt like I wasn't strong enough to do any of the storyline content and what was available was just wandering around clicking on thylacines. Sword Saint class is pretty cool though.
I'd say that Kingmaker has some major problems. I mean it's not what I'd say bad, but it has very clunky mechanics. It definitely favors minmaxing. And the line between a physical god and an useless character is VERY thin. You can hardly RP if straying from the minmax approach leads to unplayability and/or being stuck doing low level stuff.
Characterization and story are also a bit clunky. TBH I get an "amateur" vibe out of it. In a way it reminds me of HoMM5: Good intentions, good ideas, "We'll remake this classic game but *better*"... and yet you can't help but think there's a whiff of clunkyness underneath. Which you'd probably not even notice in an open-source community project, and ignore in a 10 euro game. Problem is P:K was hyped and sold as a superpremium.
IMO PoE Deadfire is a better game overall.
I didn't get an amateurish vibe from it at all - some of the writing is a bit clunky and it lacks a bit of polish, but it also depends when you played it - it feels infinitely better now than it did around launch. I agree that Deadfire is definitely more polished, but I didn't enjoy it nearly as much even though it has a better story and polish. As a sidenote, I just replayed IWD2 and I'd say P:KM feels far more polished than that!
As far minmaxing goes, I think you're completely right and it's why I recommend everyone to use the respec mod which allows you to respec all your companions. It costs gold to do it, and you can't change base stats, but it allows you to have a better put together a party without mercs or aggressive min/maxing which actually fills the roles you need. Playing on normal difficulty this changed it from being wildly uneven to being challenging but fair for most encounters. Again, you shouldn't need to with a really well balanced game, but I think it's a small compromise.
My only dislike is that pathfinder sometimes leaves you without stuff to do, and expects you to just play the kingdom game for a bit. I got confused about what I was supposed to be doing, and had to look up that I was basically supposed to just wait for the next big event to come along.