Before I answer, let me provide a bit of history.
When iMovie was released, it was written in the "C" programming language. It stayed that way through v2.1.2. Then in v3.0 it was re-written in a language called "Cocoa". The result was a product that couldn't be used for more than a few minutes before it crashed or destroyed the video footage it was being used to process. It took several releases before iMovie resurfaced as something to be trusted.
Now Apple has done it again with Quicktime. This time the rewrite was from a collection of languags to "Objective C". And voila; we have "Mavericks" and Quicktime 10.1. And another period of time to avoid Quicktime "upgrades".
Personally I don't use OSX more than 10 hours a year and then for VERY specific tasks that I absolutely can't do in Mac OS 9.2.2. So I have no clever way to give you for reverting. My brute-force approach would be to erase an unused disk and install everything that you had on the original disk on the erased disk before you let auto-update loose on the ill-fated original one.
You might also ask in a forum that is specific to OSX. This forum is actually for the older stuff that was released before X showed up.
Gary