First off, let me say that since I picked this game up nearly a year ago, I've almost always had a game in progress. I bought it hoping for something that would provide real opportunities for story-telling, and it fulfilled and surpassed those hopes by a long way. I absolutely love it.
My only quibble with the game is that for such a great story-telling engine, it somewhat lets the player down with regards to resolution. I feel it needs a cap; a full-stop; something to bring the curtains down and dim the lights after all the drama.
This could be as simple as introducing Epilogue cards (we have Prelude cards after all). Even if they're just flavour text to accompany an AO's or the investigators' victory, I'd be happy with that.
Better yet, they could also incorporate character resolutions based on the final game-board situation (provided the world hasn't been destroyed of course). Something that takes into consideration how many gates are left open and remaining monsters and/or how an investigator will now live with any injuries, madnesses or deal conditions they have on finishing the game. Maybe that's too convoluted, I don't know, but if the powers-that-be could find a way to make it work as sublimely well as the rest of the game, I think it'd be the perfect icing on the cake.
Well, that's what I want anyway (oh, and a tad more variation in AO flip-sides - I was hoping that Nephren-ka's awakening would lead to something unique amongst AOs, but it wasn't to be).
I'd love to hear what you guys think would improve the overall experience of this already incredible game.