What do you mean, how this team has operated the last few seasons? I've watched how this team operated since the early 1960's, and can tell you the philosophical differences betwen the Murchison, Bright, and Jones ownership eras. Stephen McGee ring a bell? The Cowboys saw him as a QB who could be developed - as they see Vaughan - and he rode the pine. He didn't see a regular season snap until the end of his 2nd season (2010). A few years prior to McGee the team signed a free agent named Tony Romo, and followed the same model. Once again, how many years did Romo sit before seeing any regular season action?
Do you know what "upside" means? We're talking long-term potiential, not "later on this season" potential. And what's more laughable is thinking a club thinks any player can be "developed" in half a season. When they talk about developing a player they are talking years down the road - not later in the season.
Vaughan played very well against San Diego,and pretty good against Baltimore, but poorly against Miami and Denver, but you're basing your evaluation on what you've seen in a very short amount of football. I'm sure the coaching staff is considering countless hours during OTAs, mini-camp, and training camp, in addition to what he did in preseason games. And yes, he does have tremendous upside. Prototypical build, an NFL-caliber arm, can make all the throws, and is smart to boot. The Cowboys' plan for him won't manifest itself for 2-3 years. They see him athe possible heir apparent for Romo, and not as a a potential backup for this season.