Oh man, I understand what you mean! I'm working on a game which has only one NPC and it's been already 3 times that I thought that finally, I'm done with the script and the dialogs. But as the game takes shape, I realize that it needs even more of those, and I have to go back to the drawing board. And it's only one NPC; so I really admire you guys for having the gut and tenacity to close big games of such high quality.
I think I've found out one thing, though. Most of the time, when the scene is already well-developed with a series of events/cut-scenes and all, tiny little things like a well thought out remark in reply to a question/action or, especially, a question initiated by NPC, can make a whole lot of difference. The funny thing is that those usually don't require so much effort to write as multiple highly detailed sex scenes, but to me they can really make a game.
Of course, this is highly subjective, but I think authors often over-estimate the importance of highly detailed cut-scenes and underestimate the value of a llittle chit-chat here and there. And it is truly a great (A)IF game that has NPC's that take initiative and keep the player "on their toes" as far as gameplay goes

Just my 2 cents
