As an analogy, you could apply “sifting for gold” to quite a few different aspects of football. Free Agency. The building of the infamous war room draft board. Wittling the training camp roster from 80 to 53. But the one science of football that typically escapes the thoughts of most fans is how teams decide which plays they will keep in their play book and which one's are dismissed as ineffective and/or are not complementory to the talent available.
That last bit is important to understand because the Cowboy's playbook from last year and this year should be very different. It's not so much because of the lack of success experienced with those plays, as it is due to the difference in the talent set and the difference in the coaches comprehension of said talent. Obviously, with T.O. gone, the plays that take a long time to develop very well may be all but extinct. Granted, Austin possesses some ability in stretching the defense, but it's not likely they will rely on his ability to ultimately win games, as they seemed to do to a fault with T.O..
With the trio of backs and duo of TE's the Cowboy's have, a quick strike offense is likely the direction this team is headed in. Furthermore, the Cowboy's now have a better understanding of what Felix, Choice, and Bennett can offer as weapons. The Cowboy's will be looking to put together a play book that exercises each of their talents in different ways to keep opposing defenses off balance.
With that, I would like to take a moment to remind those of you who are concerned about every report indicating that Romo and company don't seem to be insync, to consider that the play's they are likely running are new to everyone, including the veterans. The idea behind these practices are to familiarize the players with different plays and, more importantly, to slowly acclimate said players conditioning to football ready
Once preseason begins, the process of sifting for gold, so-to-speak, begins, as they determine against viable opposing team defenses what play's can be effectively ran, which players can execute said plays, and which players don't fit with the final playbook they are able to construct as a result of the success and failures they experience through trial and error.