by Anarchosyn
Hey guys (and, I hope, gals),Preamble: My girlfriend really loves narrative, exploration based board games. Whether it is phoned in a bit (Legends of Andor), or all the game has to offer (Mice and Mystics), she is giddy to explore a fantasy world in table-top form.
Descent has always been on my list, but my personal preference would be Imperial Assault based on the changes I've intuited from following the preview threads here on BGG. That said, she has a birthday coming up, so I might bite the bullet and purchase Descent and an few expansions instead (few = the Forgotten Souls cooperative expansion + whatever I glean through this discussion).
My Question: We're invested more in story and adventure than tactical combat, though tactical combat in service to story is certainly fine (as I mentioned, she loves Mice and Mystics). Which expansion really has the best narrative flow (in regards to campaign)?
I mean that in many forms, including:
a) Best subjective enjoyment of the story.
b) The best use of choice/consequence related to the evolution of story (variability when replayed is a plus).
c) Novel mechanisms in the unfolding of said story.
d) Any other interpretation you have to this question.
Descent: Journeys in the Dark (Second Edition) – Shadow of Nerekhall caught my eye due to the novel city setting, and interesting Overlord mechanism (corrupted officials, etc). Descent: Journeys in the Dark (Second Edition) – Labyrinth of Ruin looks cool because we like the dungeon crawl theme... but my experience with the full range of options is limited.
Additional questions:
Which expansion reintroduced threat as a mechanic? 
Is the narrative really the star of any of these, or should we look elsewhere? 
Per the Forgotten Souls coop thing, does it compare favorably to the Castle Ravenloft game systems (i.e. is it more fun, subjectively speaking, or just a neat and gimmicky way to play Descent)? Thanks.