Well, since it's here anyway, we might as well get back on topic.

If Story Mode's coming at all, it won't be for a long time. Doubtless the devs are focused on other things first.
I'm not discounting it entirely, though. It depends on exactly how much of a leap forward in progress Beta is.
If Beta adds most of the modes that will be in the final version, it's a possibility. But if there's still plenty left to go, then it probably wouldn't show up until the turn of the decade at the earliest. And I think the devs would be long tired of the project by then. Everyone has their limits, so let's not test them.

I do still want to know what the original FoS plans were, though. I know a summary of the first half was posted on the old wiki, but the second half was always kept under wraps and is presumably lost unless one of the devs from back then still has a copy.