Ok, we are back at the point where people who do not see a feature they need in blender start to invent a new app, often a rewrite a commercial one that we do not want to pay for. Here starts the trouble, so what is a parametric modeler? By definition it is creating models from parameters, thus changing parameters reflected in the model. You can do all kind of stuff with that idea, in 2d, 3d, on meshes, solids, generic objects, text... it does not define a cad yet.
I see two successful concepts of 3d applications. One is offering a great toolbox for one field of modeling, e.g. a great solid modeler, a cool 2d sketching CAD, a powerful mesh modeler. The user than uses tools from a pallette of apps, modeling solids in the modeler, drawing a plan in 2d cad etc, finally importing everything for rendering and output (rendering can be a raytracer or a 2d drafting/layout tool). The other way is not to write apps for the type of data that is worked on (solid, surface mesh etc) but the useage expected. As I understand that is how Blender developed, a tool for 3d animations. With that approach, the tool gets almost unuseable for anyone else of course, and here is the reason for most complaints about render. Do you want to make design (scale of mm, m, km?) requiring accuracy, simulation requiring simple but clean solid models, animation with high polygon count surface models and anim support, game design with low polygon count...?
Too many try to put everything for everyone's useage scenario into an application, that won't work. I think in open source the tool pallette concept works better, we have ways to do solid/csg stuff, surface meshes etc. The missing parts would be the solid cad package (that is what pro/engineer would refer to) and a really good 2d cad able to exchange data with the 3d foss tools.