Frankly I feel that the only aspect of BG2 that didn't "age that well" is its technical obsolescence: natively designed around a very low resolution, with an abysmal default frame rate, etc.
And you could make an argument for the inventory system being a bit more cumbersome that it should be. Which ironically enough is a complain that can be applied to BG3 as well.
Overall, I agree. I never have any problems playing BG2 over and over. It does have to be said that one aspect you don't mention is the problematic pathing in both BG1 and BG2. I can't tell you how many 'accidental deaths' resulted from the pathing taking my party members places that they shouldn't have gone. "Imoen, why are you going the LONG way around?????"
