I'm working on this dilemma right now in LibreDWG. The problem is not the script to represent the parametric links and expressions, the problem is how to translate the database entries from one system to another.
Both systems are using scripts only, which need an interpreter and are therefore extremely system-specific islands.
Better standards come from SolveSpace and AutoDesk, and the industry formats STEP and IGES.
The problem with AutoDesk is that it's a closed and undocumented format, representing the various links and expressions between entities.
The SolveSpace modeler is much smaller, much more powerful and much easier to use.
Imho needed are converters from the most used tool, AutoCAD, to the other tools, as mentioned, if CSG or B-Rep based, which carry better information than just STEP/IGES.
