Thank you! I just made a new world and it seems to be OK. However, is there a way around this? I'm really not interested in the whole cavern and magma sea thing so much as I am the military and medical changes.
Alright, I have an idea, but I'm not particularly sure it will work.
Likewise, it may result in strange in game behaviour.
Step 1.
Open the file "Plant_Standard" in your RAWs folder.
Modify all plants you want on embark from "Biome:Subterranean_water" to "Biome:Any_wetland"
Remove the underground_depth tag.
Essentially, this turns underground plants into above ground plants. May result in strangeness - humans and elves bringing you plump helmets, for example. Also being able to gather them outdoors.
Step 2.
Open "Entity_Default"
Turn your dwarves into humans, essentially.
Add the tag "Outdoor_Farming" to dwarves.
Change the "start_biome" tag value from "mountain" to "Any_grassland", to ensure that they will actually be able to farm.
You'll probably see dwarvan caravans arriving with stuff like "Sunshine" and "Sun berries" because of this.
So, no promises on whether this will actually work, and no promises on whether or not this will result in gameplay weirdness.
don't dig down?
try and find a mountainous area in which you can dig a good deal of z-levels without disturbing the caverns or magma layers (which are often quite a ways down)
It's not that easy - the underground layers can still sap a not insignificant portion of your CPU/memory due to the current pathing weirdness with undiscovered layers, fluids, and critters. Not to mention the shear number of layers available to view.