Im perfectly fine with undead showing up in fortress or adventure mode fully armored and with a weapon. What im less fine with is the sheer quantity that they come in. I love the undead in dwarf fortress, and being honest i like the sheer threat that twenty or so armed and armored zombies provide. Especially since they typically have some level of skill with the weapon they brought. I also dont mind an unmeetable invasion force. Suddenly being unable to access the surface isnt the worst problem in the world. I mean the undead can typically be stopped by a door. But zombies are almost always an unstoppable force. Which gets old, when the second invasion in two years is 80 undead strong, all of which are trained and well equipped humans/dwarves/elves. They even have metal arrows, and some have steel weapons. What happened to the swarms of peasants that must have made up the bulk of their forces in worldgen? You cant exactly start with 20 armed soldiers to kill more with.
As a result i think there’s something that could be done to benefit the undead to make them more fun to deal with. Instead of all the undead being trained soldiers with weapons. What if only about 20% were? An unequipped zombie is still a solid threat, then you could have large numbers of undead utilizing the swarm attack style that is classic for them, without them being TOO strong.