Patremagne: Is this really going to be the only way to get mods on the GOG version? Seems very roundabout and inconvenient.
It's a bit of a pain, but I tested it and it works without a hitch. It's not much more hassle than downloading something from Nexus or some other site that often also needs accounts or something.
I did find out that you need to run the launcher before the game creates the archives and the mods start working. Using a direct short-cut (as I'm used to) doesn't work. But you only need to do that once.
On the plus side: I now have a neat re-skin that makes my mounted archers look like actual units from that race, instead of getting Elves with Mongolian hats, and another one that really improves how different hunters and shamans and such look. I'm looking forward to seeing what more ambitious projects will materialise in the time to come.