"... but not likely to be the only way to do parametric editing."

Yes. Please take into consideration also something like the "Components" from Sketchup or Blocks from Rhino, or iLogic from Inventor. They are also very powerful parametric design approaches.

MoI can be more powerful than Sketchup (already is in many ways) but is drawn back by the lack of "components". Personally I think that if the MoI will have something similar to components will be a serious option for replacing Sketchup.