SF_Green
I realize doing a 1 to 1 replacement will probably never work. But what could be possible that would be very helpful would be to at least recover the name of a patch or preset that was loaded in the plugin. That way if it's an older project I'm coming back to I would at least have some idea of what I was doing in that track and could set setting else up much faster.
I share the frustration of having older projects with plugins that may not load or even exist on my PC anymore.
What I learned to do since those days was to:
1. Create a version of projects with synths bounced, to preserve sound if I have to rebuild later and don't have the synths for some reason.
2. I now tend to save any sounds I have either built from scratch or created using some preset as a base and tweaked for a particular project - so I now save those presets in 2 places - once as a preset saved in the project folder, so it will always be local to the project that uses it. I also save the presets off in a User Preset folder I generally set up for every synth, so that I can use those custom presets for other projects (either intact or as a base from which I can tweak for the other project).
3. I also now create a sub-folder within each project folder, called Project Notes, and there will be one or more text documents containing editing notes, project notes, track notes, whatever is needed for that particular project, and this includes what synths are used, what effects are used, what presets are used for each synth, and any info on any patch construction, etc. All this info may seem like overkill, and I always hope that it is - but it has also saved me lots of pain and agony when things go South after some lengthy time has passed and I cannot remember details when I need them the most.
I highly recommend you give some thought to what info you might find helpful to have stored outside each project, so that you can rebuild or at least get close to how it was, for any occasion where things fall apart.
Bob Bone