Wow, plopping a fortress down in an evil region is going to be mental.
It feels like every new version gets darker and darker - call me an elf if you want, but I hope 'light' 'magic' gets some love at some point. Maybe not Rainbow Bright / Carebear levels of love, but maybe random charms for armies combating the evil forces of darkness in good biomes or something...
I can't help but hope he doesn't really go that route, in a way.
While I'm not fond of the notion of a grimdark world where there is overwhelming corruption that is unopposed and will inevitably bring down the universe into zombie apocalypse land, I'm even less fond of seeing Dwarf Fortress become just another High Fantasy.
For reference, High Fantasy means something like Lord of the Rings, where the heroes (or player, in this case) is just a pawn in the game of a cosmic war of good and evil, and everything in the fantasy world is defined by what side of that line they stand upon. By being creatures that aren't part of the "evil" category, and opposing skeletons, that makes dwarves have to follow "good" just to survive, and I'm pretty sure we all rather prefer the option to be the most evil things in our particular universe.
Adventure Mode Dwarf Fortress works much better as Heroic Fantasy (think any "knight in shining armor" story, or any anti-hero spoof thereof) where there are bad guys and heroes, but it's always about the individual hero's choices making them heroic, rather than the cause they represent. (Or, alternately, a Puss In Boots being simply a manipulative bastard who lies, cheats, and kills everything standing in the way of getting himself and his master to power, and somehow still gets called "heroic".)
Fortress Mode is probably best as Low Fantasy (Think the Thief series) - cynical, mechanical, and pragmatic more than epic. It's just high on magical creatures for a Low Fantasy.
I'd rather see something like a sphere of War or a sphere of Fortresses that can somehow crowd out the sphere of Undead, or at least cut into its power supply, so that we aren't engaging so much in a battle of Good Versus Evil as a battle of Red Versus Blue.