Pillars of Eternity is an especially interesting example. Confusing and unforgiving health/endurance bullshit, annoying and sometimes game-breaking bugs in a game with story this long make me afraid to touch it anymore really and playing it I think I might just want to get back into Icewind Dale II and its familiar mechanics that are somehow seem easier to manage even though they're objectively much less intuitive. Because I like my games easy. Or at least easily trivialised. I don't want to be stressed, or rather, not by not being able to figure the strategy in time before I just lose interest.

I'm also playing Pillars of Eternity right now. What difficulty are you playing on? I'm playing on normal right now and I don't think it's as bad as you're making it out to be. The bugs are bad, but I haven't encountered one yet, with the exception of crashing at Raedric's castle which could be fixed by messing with the savefile.

The health/endurance thing is actually pretty simple. Endurance is basically your "health" per encounter, they act just like HP in any other games, when it goes down to zero you get incapacitated for the duration of that encounter. There are spells and talents that can heal up Endurance.

Now, Health is basically your "life". They go down together with Endurance but they're a few times larger than Endurance (just for example, let's just say they're 3 times larger). So what does this mean? It means if you get incapacitated 3 times in 3 different encounters (assuming you didn't heal your character) then your character will get "maimed" if you're playing on Easy or Normal difficulty. When they're maimed, both of their Endurance and Health are down to 1. If they get hit just one time, then they're dead permanently.