While OCL isn't mandatory, yet, some features will not work without it and personally I'm starting to get a little concerned that so much effort is going into a library that is currently incompatible with Python3, (now the default with FreeCAD). OCL might not ever be able to build with Py3 unless it undergoes a complete rewrite, and I don't think/know anyone that is doing that. To continue down the road with what could easily become an obsoleted and unusable, (to FreeCAD), library, I don't know...
With hind site being 20/20 and all, perhaps Path should of started out as a project to write a CAM kernel that was a part of the FreeCAD package, instead of relying, even a little bit, on external, unmaintained 3rd party, incompatible licensed, (it's still incompatible, right?), products.
Please, no one take this the wrong way, just my personal observations. I in no way intend to offend anyone doing such excellent work on Path, just putting out a users perspective, and perhaps a little frustration with this current OCL mess.