Looks like Neverwinter Nights 2 has been freed from rights hell and is due an imminent enhanced edition release, bringing the 2006 RPG from 5GB to 36GB

It's been a while but AFAIK you control three or four party members so it's more like the older BG games than NWN1 in that regard.

Storywise it's set in the Forgotten Realms near the regions of the first game but it's a completely new story with new characters. Iirc the story manages to decently subvert some expectations. I remember a conversation with a dead god in the expansion that was on par with meeting Sovereign for the first time in Mass Effect.