i really don't think it should be reversed. it's unfortunate, for sure...but it's part of the game to live with a blown call.
and yeah, you'll open up a HUGE can of worms if you allow a call to be overturned.
While I don't think this call should be reversed, I really hope that this situation will make video replay available in the future. It sucks for this perfect game to be blown, but if the MLB and Selig can implement changes to prevent it from happening again then I think this blown call will make the MLB better.
Also, what is with all the no-hitters and perfect games this year? Almost 3 perfect games and a no-hitter in two months. Have I missed a lot of rule changes favoring pitchers? Or did the steroids really improve the batters that much? Overall are pitchers performing better or worse than historical averages.