There's a small problem with many epic-sized games, specifically with the Western-style RPGs: multiple paths through the narrative elements in the game require multiple play-throughs to experience.
Well, sort of. Not really.
The main story arc tends to remain untouched. But choosing good or evil has certain repercussions on sub missions and specific dialog options. There are also multiple romantic story arcs to follow (at least in BioWare games). Trying to keep it all straight tends to get confusing. Epic RPGs used to be simpler. Or maybe it was just JRPGs.
I could re-play Final Fantasy VII today and still get all of the narrative and expositional bits that I got almost a decade ago when I first played it. There are no real choices in that game. The narrative drags you from location to location and feeds you information while you smack monsters of increasing difficulty with swords. It's very linear. And as such only needs you to play it once to get it all.
Not so with many newer games which bombard you with all sorts of shallow (and narratively meaningless choices) that affect how you play and which parts of the dialog trees you venture into. Boy or Girl?
This first trip through the world of Mass Effect I played a male Shepard on the Paragon path, and chose Liara T'Soni (the hot blue alien) for the romantic sub-plot.
Next time I want to run the game as a male Shepard on the Renegade path, and follow the Ashley Williams (the hot space marine) romantic sub-plot.
A third play would see me as a female Shepard trying to balance Paragon and Renegade while persuing whatever romance seems most interesting at the time.
At 30+ hours per play, that's a lot of time for a single game. I suppose that makes for a good marketing bullet point.
And having these choices makes the game feel epic. You have to choose, and then you have to live with your choices for the rest of the time you play. Shallow as the options tend to be, they are still choices that you are forced to make that have lasting effect on how you experience the game world. You've invested so much time that restarting to alter a choice becomes daunting, and the idea of managing all the possible branches at once is mind-boggling.
These small choices force you to choose, and that makes for a good story. At least for me, because part of me wonders how it could have turned out differently. Good thing I can find out, given enough time.