Now That I see that the legion mod you can create maps with many many characters and the fact that I kind of dig the turnbased approach of D:OS, it makes me wonder. Would anyone out there be able to create an xcom/Xenonauts type game from this editor?

You would have to create a shitton of assets to use freely. Can't steal assets from other games.
To create a total conversion would take forever. Think years.

yeh this editor is pretty powerful so it is possible but as its said before it takes a long time