I always thought that Mask of the Betrayer was fucking weird to make as a sequel to NWN2: OC for several reasons.
1.) The story that they tell in the game doesn't match the levels. It's a fucking cRPG so you kind of have to expect that, but if MotB took place from levels 12 to 22 instead of 18 to 30 it would've felt less dissonant. It's unavoidable, unfortunately, since NWN2 takes you from level 1 to 18-20 and MotB is a direct sequel.
2.) The party dynamic in that game feels way different than NWN2: OC. First of all, the NWN2 companions except for Shandra, Sand, and Ammon were either obnoxious or non-entities. The intent was to have a classic Scrappy Bunch of Misfits gelling together for a common goal but they felt too snippy and self-centered to ever have anything click. The vast majority of inter-character interactions felt snippy and hostile.
In a way that works for the game because it feels like MotB's interparty dynamics feels more 'mature' (as in, more adult and rational) than the OC. On the downside, there's a lot less companion-to-companion interaction in that game. Which is actually a pretty large pity, because with one exception your companions are a lot more agreeable and reasonable.
The only real weakness of NWN2's companion system is that they're too passive to evil. Your companions will only leave you if you're
blatantly doing the whole Killfuck Soulshitter thing and you have to go pretty damn far. Which in a way is unavoidable because the cast is a lot more pared down compared to NWN: OC and you won't even notice it on a good/neutral/reasonable evil playthrough. But I'm sure it grated on K's playthrough.
3.) The tones of the games don't match, like, at all. OC was a classic 'lighthearted stumble-bumbling fantasy cliche adventure that gelled into something more serious in the endgame' which really didn't mix with MotB's 'heavy-handed and dire ruminations on dreams, family, morality, and defying fate'. Again, that choice may have been intentional to emphasize the maturation of the plot but it still feels weird as hell.
Also, while NWN2: OC already shit the bed with
its craptacular (though not as craptacular as MotB's) ending it might have been asking too much for MotB to retcon more of the fail of it. MotB only partially retcons it by revealing that the less annoying characters survived while the more annoying ones
(the blatantly evil pyromaniac sorcerer dudette, that absentminded wannabe tinker gnome dude, that bland paladin dude, that smug ranger dude, the personality-less golem, that obnoxiously hyperactive tiefling rogue dudette)
didn't.
Now that I've partially calmed down, I would really like to analyze those two games. Except for the motherfucking, shit-sucking Chrono Cross of an ending of MotB's good/neutral playthrough I still contend that it's one of the best cRPGs out there. NWN2: OC is deeply, deeply flawed but there's still some gems in it. It's an entertaining trainwreck at any rate, like... oh... Final Fantasy Tactics or Advance Wars: Dual Strike.