This is totally plausible. The problem as stated is the maps require using 3DMax. Since there will always be people adventurous enough to do this, the hang up we have is a map editor.
You will be happy to know that a map editor that allowed the placement of the citadel, towers, portals, flags, fortresses, and other objects already exists. It was actually available during the beta and a number of us played around with it. The ld editor was backed up by a number of folks, but no longer appears to work with game version past the 2nd beta phase. However, they stated they wanted to add mod support and if demand was high enough and they had a reasonable amount of purchases, it was totally foreseeable that they would release an updated map importer/editor.
Again this requires existing 3dmax fields as a base, but they certainly have a map importer/editor already.