I did not mind the original campaign so much (I liked that it seemed less grimdark and more quirky than typical CRPGs), but its biggest flaw was how long it was. I’m pretty sure it took me more like 50-60 hours to finish the main quest, or maybe it just felt that way. It does that annoying thing that these games have the tendency to do where it takes you several hours to even get to the main area (Neverwinter in this case) and for the story to really begin. In the meantime, you’re romping around swamps ad nauseum. I do remember really loving one of the things at the end where your main character’s relationships with other party members gets tested that can alter the nature of the final battle a bit. Usually, these games only use relationships to determine which person your character sleeps with at the end, so it was nice to have something a bit more substantial and interesting happen. As mentioned by pretty much everyone, the expansions are better though and I would personally be hesitant to play through the original campaign again.
I do not think that the mod scene for NWN2 was ever as robust as the original, which is unfortunate because it’s a better game in nearly every regard otherwise. I do recall an adaptation of one of the old pen-and-paper modules for it being really good (Cult of the Reptile God or something similar), so I would definitely recommend looking into that if you want some more stuff to do after playing the expansions, or maybe if you are looking for an adventure with a more reasonable playtime.