Understand that I know nothing of programming or anything else, but here is an idea to change the maps a little.
First add trenches from lake to lake. They can be static as in the train tunnels. Wasnt much movement in them anyway during the war. This would just be scenery change.
Second, here is the fun part, randomly generated anti aircraft guns. AI controlled maybe. Both sides could have them and if you flew too low over one you might get shot down. Thats how the Red Baron got his. And the death would count in your stats.
Like I said, I dont know anything about programming, or code writing, or whatever, might be a nightmare to put into place.