Having some very basic joint functionality similar to some of the 'as built' joints found in Fusion 360 would be a real boon for any kind of product development, even just sliding and revolute joints with end limits to help visualise how parts of a design might interact. This might also be useful for artist/game developers as a much more simplifed form of rigging like would be done in blender, but much more suited to mechanical type assets (gun slides and triggers for instance).