HH, you and I aren't that far apart (except I don't want Garza anywhere near the Braves' clubhouse). The Braves tried your approach in a limited way with the Cahill and Arroyo trades. There are clearly more expensive guys that that would fit into the same mold. I think Kelly Johnson, Jim Johnson, and Juan Uribe are all examples of bringing in lower cost FAs and hoping they have some "flip" value during the season, which all of these guys had (which doesn't necessarily mean the Braves got value for them when they traded them). Swisher and Bourn (to a lesser extent) fit into the approach you outlined as opposed to the Braves' initial approach.
What is different about this year (and likely next) is that we don't have minor league guys ready to assume the vacancy of a traded (or released) veteran. That probably changes a bit over the next couple of years as more guys become ready to contribute (read, not embarrass themselves) at the big league level. Even with the guys we traded, we're a low-to-mid 70s win team and we probably have a protected pick. Without the guys we traded, we simply don't have a big league team on the field, especially in the bullpen. It has just been so disheartening to watch this team over the past month and a half and this is coming from someone who felt that a rebuild was going to take place at some point and is ready to take the lumps inherent in a rebuilding effort.