TodashXIX: There is likely a lot of crossed wires and conflict about the story, where to take it, how to get there, what to focus on, how it all ends, the type of game it should be, etc.
It's a creative project that has, at different times, been handled by different people through the years. It's a massive undertaking, even if you ignore the coding side of things.
And people, particularly creative people, would rather not release something that isn't going to be appreciated. They would rather hold a thing back than have it mocked or anything. So they wouldn't want to rush it, or put out a half-assed product simply to get fans off their back.
And they aren't the first company to do so either. Blizzard canned Ghost, etc. When developers get big enough that they don't have to penny-pinch just to survive, they feel safe enough to produce quality over quantity. And if something doesn't meet their quality standard, then it doesn't get released.
Or it could be as simple as they are still stewing over it, hoping that they will have a brainstorm and it will all just fall in place, at the right time.