I would like to propose having the ability to edit the Inherited permissions but only if you want to increase the permission level within Design Collaboration then you would not have to do a workaround to get the permissions needed within Design Collaboration.
Currently the folder within Files that a Model is stored in brings over its permissions into Design Collaboration for that Model. That makes sense but what does not work is the fact that the permissions are set to Inherited and greyed out so you can't change the permission level even if you want to give a higher level. The workaround is to delete that person, role, or company from the folder permissions then add them in Design Collaboration with the appropriate permission level, then add them back to the folder with the lower permission level.