Downgrading
If one wants to go back to QT 7.4 or earlier, we return to the best solution we had when QT 7.4 broke several things, such as After Effects.
Go get the program Pacifist and an older installation of QuickTime. Use Pacifist to have the older version of QuickTime install over the current QT files on the system. Then reboot your computer and you should be back to the older version of QT.
AFAIK, you would have to do an archive/re-install of OS X. I am sure someone will correct me if I am wrong.
If one wants to go back to QT 7.4 or earlier, we return to the best solution we had when QT 7.4 broke several things, such as After Effects.
Go get the program Pacifist and an older installation of QuickTime. Use Pacifist to have the older version of QuickTime install over the current QT files on the system. Then reboot your computer and you should be back to the older version of QT.