I'm pretty sure what I've isolated is something akin to vision for backs that have NFL-quality physical tools. If a back has elite tools but doesn't produce it stands to reason that it's because he doesn't process game action in a way that lets him use his physical advantages. Assuming no problem with work ethic, character or injuries.
But for backs like Franklin it's possible that my vision metric doesn't work the same way, and that what the poor numbers actually reflect is his lack of physical tools. In other words, all the vision in the world won't matter in the NFL if you can't compete physically.
It's also the case that this metric is forward-looking. It's not just looking at what a back did, it's looking at what a back did, adjusting it for some things that affect the score, but aren't related to vision/skill/talent/whatever you want to call it and predicting how that will translate to the NFL.
That's a little tricky since it's holistic -- the pieces interlock. So some players need much higher scores on the vision (skill/talent/whatever you want to call it) front than others do in order to make it in the NFL. There's even a small subset of backs with negative performance scores that have done pretty well in the NFL. If we had access to NCAA game charting (like PFF does for the NFL) I'm pretty sure I could sort out why that happens, but for now I just note that there's a certain type of back who translate to the NFL very well.
So when I talk about Franklin's vision, it's in the specific context of his physical profile and is being measured against similar backs who succeeded in the NFL. He's obviously much faster/quicker/better than 99.9% of the human race, but that's not what we're interested in.