All right, I lied. I took some time and put together a changelog of sorts after all.
I've separated my changes into two archives:
Full(a dump of my X-Com Files mod directory) and
Lite(a pruned version which should contain only the changed files; eats less space and gives a better overview of what's changed).
The documentation is contained in both archives and is also attached below.
I'm not interested in either getting or giving credit, so consider this a 'modder's resource' that borrows heavily from a number of people's work. I'm releasing it for free, no strings or requirements attached, but if anyone wants to use it in a public mod, they should credit people I've stolen from (most of whom should already be on the FMP credit list).
Hope my ideas serve as inspiration to somebody and good luck to Solarius with the monumental task he's taken on himself.