I still am impressed with dm-Falkenstein, it is a work of Art and very ambitious. It ran decently on my old Voodoo 5 5500 and runs perfectly fine on my Radeon 9600 Pro. As for Gameplay, it probably would make a good As/CTF/DOM map, it was too big for DM.
It would be interesting to see the Castle put into a UT3k3/4 Terrain with some Grass, Shrubs, and other updated Unreal Engine goodness.