This is sort of on topic here, but I've had a number of times where I wish you could turn back the clock. To many times not saving a patch, because I decided to tweek some more, as that great sound I had, withered away. Any chance for the undo?
How about a session save button? You would use it at your leisure. What it would do is perform a save about every 30 seconds or so to an Omnisave folder. The files might be named automatically, save1, save2, save3, save4 .......... save89. They stay on your hard drive as long as you remain in that instance of Omni, If you close out that instance of Omni, all saved files in Omnisave folder get erased. That wouldn't be complicated, would it?
Here's what I do to prevent the library from getting floaded with "in between save patches":
I simply click the disk Icon in the VSTi window...and save the patch with a name...and a 1 or 2 at the end. In that way it is easy to go back to the previous patch I liked...but messed up by tweaking parameters that have the unwanted end result.
You can always delete these patches from you harddrive when you need to...when your patch is finished.