Oh, by the way! It would be cool to introduce creatures from Slavic mythology into a swamp add-on—if it ever actually comes out—like leshys, vodyanitsas... Baba Yaga... stupid, of course... but original.
And in general, more diverse neutral creatures like mummies should be added to the editor. You could take someone (and why not everyone—they're neutrals anyway) from previous parts. In some 3rd part there were boar riders. That was also wild.
Now, it would be wild to put Koschei the Deathless in the Necropolis instead of ghost dragons. Bone dragons already seemed questionable to me back in the 3rd part. The Necromancer brought them to life! Ooooh!!