First off, there is no way that trade should be overturned. It is extremely debatable who got the better end of the deal. That said, I'm going to be the voice of dissent here... I think the other guy got the better end of the deal overall.
This year, Braun+Lester+Young+Oswalt >>>> Heyward+JJ+Timmy+Smoak (Braun >>> Heyward, Young >>> Smoak, Lester == JJ, and Timmy >> Oswalt)
Long term, if you only have 5 keepers, then all you did was swap Braun+Lester for JJ+Timmy, and I'd always rather keep hitters so I'd prefer Braun+Lester in that case.
Long term, if you have 6 keepers then you should make out better, but its not a foregone conclusion. You are basically swapping out Braun+Lester+Santana for Timmy+Johnson+Heyward. In that case, I think Braun>Heyward (Braun >> Heyward in 2011, Braun == Heyward in 2012), Lester==Johnson, and Timmy >> Santana (Timmy >>> Santana in 2011, Timmy > Santana in 2012).
So bottom line is that if you are out of it this year AND you are definitely keeping 6 players, then you might make out in the long run. But if you are still in the running this year OR you are only keeping 5 players (or both), then I think you lost the deal.
"The government cannot give to anyone anything that it does not first take from someone else"