[Endoperez]

I don't know if stats and magic could be left to the .dm while all abilities #clearspec affects are left to the .exe/.dgf, or if all changes into a unit should be done only one way.

Without thinking this much, I quess it would be enough if every unit/nation/theme is only modified in *either* .dm or .exe/.dgf . At least in the case of units and their special abilities, it seems that adjusting the same thing in both .dm and through changes in executable is just too much work for its worth.

If your GUI isn't harder to use than directly editing .dgf-files-changed-readable would be, I have no problems regarding .dgf files not being plain text files. Most people seem to avoid modding because they don't want to go through the hassle of learning #commands, so the people who start modding with your GUI probably won't even miss the option.