He's a straight-line runner that lacks ideal burst, acceleration, and top-end speed. He doesn't cut well, nor does he run with power, although he runs hard, he doesn't break many tackles.
Vaughan is basically a poor man's Michael Turner if Turner was 30 pounds lighter. Like a declining Turner, he has a tendency to stop his feet when he gets into traffic, which is a no-no for a RB.
Also the fact that he's been cut by 5 teams also is a sign. Even in the instances where players go on to have success after bouncing around early, usually it's only getting cut 1 or 2 times. See Ed McCaffrey, Brian Finneran, Wes Welker, Tramon Williams, James Harrison, Ryan Grant, etc. If you got "it," usually by the time you hit your 3rd team, you'll show enough of it that they won't let you slip away.
The Falcons have 1 of the better 3rd down RBs in the NFL in Jacquizz Rodgers. So it begs the question where does Vaughan fit? I'm of the opinion that Vaughan is a capable No. 3 runner, which in my parlance is basically a guy that is only going to play if there is an injury to a player ahead of him on the depth chart, as opposed to a player like Quizz or Snelling that is a No. 2 that can be a regularly featured member of a committee system.
Snelling is likely a goner come 2015, so is Vaughan going to replace him? Perhaps, although he'll be hard-pressed to get reps like Snelling. Snelling only gets the reps he does because he too is a very good 3rd down option and is also versatile, able to play multiple roles (FB, ST), two areas where Vaughan is unproven (FB) or weak (ST).
Even so, that really just represents a No. 3 RB and thus there is no real reason why he needs reps now to develop into that role. So the only reason to give him reps is if you believe that he's capable of being a No. 1 tailback. And I say unequivocally that the answer is no, he is not.
Could I be wrong about Vaughan? Certainly. Heck, I said Darrin Walls wouldn't amount to squat in the NFL, and he's doing a pretty good job in New York, outperforming a trio of #1 picks.
"Vincere scis, Hannibal, victoria uti nescis" -- Maharbal, 216 B.C.E.