I will agree with the assessment that IWD2 was indeed a much better role-playing game, with a much better story (I might add) than Neverwinter Nights. The combat in IWD2 was dull, at best, but it was never as horrendously crap as NWN. To this day, I still consider the Infinity Engine games some of the games I'll remember fondly for being some of the lucky few games I actually bothered to complete, and also for providing some of the best atmospheres I've ever experienced in any game.
Saint would probably disagree with me on the whole atmosphere business, as they didn't really provide much in terms of choices and such, but speaking in purely story-based aspects, those games had them nailed right in the head. They weren't very good with the whole 'choices' department of RPGs but they definitely had a good narrative. The stories themselves might have been uninspired, especially with BG and BG2, but the narrative was always gripping, in spite of the hackneyed plots.
The one thing that the IWD games had over the BG games and a lot of others was the fact that the plot was not so hackneyed, and the characters involved seemed 'real', inspite of the fantasy setting. I liked the whole bit about how the twins were driven out of the town after their mom had been found slain and their house burned to the ground by the villagers. I mean, really - it's those sorts of little details that JE Sawyer and MCA put into the game [IWD2] that went a really long way with me. The thing about these two guys, is that they brought their games to life, especially MCA with Planescape: Torment. You could sympathize with Ignus, and you could relate to Morte's plight. Let me ask you, how many games offer that degree of immersion?