I would like to suggest adjusting some spawns in specific areas.
For instance... the Dark Dwarven Tunnels have 3 types of creatures that can spawn together... Dark dwarves, Umberhulks and Beholders.
It would be nice to slpit the dwarves off from the other 2 so that they do not spawn together.
Umberhulks and Beholders on the outer tunnels and the Dwarves closer to the Dwarven Fortress.
I think little changes like this could help give the areas a more realistic feel.
If anyone else has any other areas or ideas on this please post.