The fact that we're still a mid-market club that needs to be leery of starting players' service-time clocks before they're absolutely ready comes to mind.
Count me as one of those who wants to see it before I'm completely sold (like many of the naysayers), but also as one of those who has seen La Stella several times personally. While I'm far from anointing him as a future All-Star, I also believe he has the plate discipline, eye, and makeup to be an above-average regular at the position.
The reasoning behind the Gosselin call-up and Johnson signing were pretty simple IMO - the organization is well-aware that Gosselin will never be a regular, but they needed someone capable of playing 2B...Pena, Uggla and Patornicky were on the DL, and Johnson was still in KC. Considering Pastornicky and La Stella are the next two internal options at the position and hope existed that Uggla's surgery was actually going to help "fix" him, there was absolutely no reason to start La Stella's clock prematurely (hence the Johnson desperation signing). Looking at the situation in the overall scheme of things (long-term, not 2013), I'd think it'd be tough to argue Wren's perspective - "If we don't have enough offense to compete in Heyward, Justin, Freeman, Mac, Johnson, Simmons, and Gattis, we're not winning anything unless we add a significant producer in Uggla's place." The organizational philosophy has always remained consistent - they're willing to turn the keys over to young kids when they are convinced that they're "ready" to be helpful every day, but they're NOT going to start their clocks before the brass is convinced that time is now. The production difference between Uggla/Johnson/Gosselin and a wide-eyed La Stella in the heat of the postseason was going to be negligible at best, so they weren't going to start his clock.
Unfortunately the Braves will continue to have to make decisions like this until ownership changes and service-time and arbitration eligibility aren't overriding issues.