>Also - passingin a parm object doesn't completely decouple anyway - both the form and calling method still must make some assumptions about the structure of the object. Pick your poison!

If the called object is supposed to fill in a property on the Parameter object that doesn't exist, it could easily do that with AddProperty(). Then you'll get the same object back every single time from the called object, instead of a modified version of the calling object which could be different every time.