Well I don't know how you'd go about making a bonafide map editor, since all the maps are 3d meshes, but if you can do it more power to you.
I am sure all the information available is accurate
, it just may not be the full picture because, as you said, the authors of those tools have stopped working on them. You may want to try to talk to magnusll
. Usually I'm averse to name-dropping, but magnusll has recently been working on some similar tools and as such I can't think of anyone else who might have the kind of insights you're looking for.