The fight I'm talking about is the big final one, basically, and my problem is not so much any part of the fight in particular, as the fact that you're apparently supposed to fight several fights in a row without being able to rest inbetween. Which I guess my party just isn't built to do - I heavily rely on my high-level sorcerer PC and her ability to summon planetars, and cast dragon fire several times in a row until everything is dead (ironically, that dragon fire spell is as it turns out surprisingly effective against dragons). After a few of those fights without resting, my sorcerer would be finished in terms of high-powered spells, my healers would be out of resurrection spells, and even with good gear there's only so much you can expect Sarevok to do on his own.

The fights in Throne of Bhaal were not actually super hard other than that, I thought, though a few did force me to reload several times - but your characters are powerful enough at this point that there are lots of strategies that will work (though I feel my sorcerer PC was rather more powerful than many other PCs might've been, that helps). Not like that one fight in BG2 where Irenicus uses his "kill everything instantly" spell and you're wondering how on earth to deal with that. Or that adamantine golem that can only be beaten in extremely specific and generally rather lame and slow ways.

It's actually a frequent enough thing with me, though, you can call me weird but I just don't care that much about the battles in these games, or not if they take me too much effort to win anyway. It's hardly the only campaign or NWN module that I've abandoned after having gotten to a fight that was too hard or too annoying, especially if there seemed to be little story left beyond that fight. And I was pleasantly surprised to find out one can bypass the final climactic fight of Hordes of the Underdark altogether, and beat the bad guy without the fight. I could always go back to a saved game and fight him, but I doubt I'll bother.