Not to mention it's always easy to make an argument when you only form one side of it to fit how you'd like to see it. Really though, we have to get over this first hump of how the heck this can be "quantified" as said above.

You have to underestimate the impact of one in order to assume the other is so superior.

I get that in reality the only thing you're trying to argue here is the "potential" of one, vs a "known" for the other. But you really have to actually think it through before you can make such an assumption. There's no way for you to say one way or the other. Just however you want to see it.
The presence of a "risk" does not guarantee the potential outcome is lesser. Being harsh on Mangum would still only make it high risk high reward... And the high risk part is a bit unfair since he IS proven as a player.

Don't underestimate the game of football. Everything is tied together and affects all parts. In certain games, the increased performance in the passing game not only helps the obvious of passing, but makes defenses RESPECT it, and opens up the run game. That alone with Jamaal is almost a guaranteed win in such close games. (Yeah i know someone will want to argue OL, WRs, yada yada).

The idea is that the passing game got to such a low, it couldn't have hurt that much to try. And if there's an increase in performance, it absolutely changes things. If you can pass, there's less of a NEED for Hill's ability to run. Does this not make sense to many?

In the end this last statement above is what it comes down to. The need is lessened if the other aspect is there. This is true for Hill himself. Also, don't be so quick to devalue Mangum's legs. He spent all year behind a struggling OL, using his legs to scramble and buy time. This isn't something new. He doesn't have to use his legs to run, if he can use them to get a completion.

You're drastically underestimating the impact of something in order to "see it a certain way."