A few days ago, I was working on a videogame soundtrack with MODPlug and many VST.
Something weird happened : beginning a session, I started to load the music I was working on, and during the process, I got a "Error Replacing" message for several VST.
The big problem is that all VST that were signaled by this message had to be reloaded, and above all, I had lost the presets I did for this musc for each of thoses "replaced" VST.
So, of course, a solution to avoid loosing them, in the future, would be to save each preset.
But it would be far more comfortable, I think, to be able to "Save all VST presets", an action that could create as many VST preset files as there are in the song, with their name and/or FX number, so no risk anymore...