Cool stuff, Alex! I really love the validated direct operations, much better than having to assign cmdProcessor calls to a nodeset variables and xpath them to determine the results.
But why do you loop over a list of XML attributes and create the association and op-data in small pieces in your "contrast" example? Does a simple
not work here? Would also be easier to follow than the dummy attr option, imho. Add your clever set/clear op-property trick and that's what I'm going to use.