The template loaded when I create a new Schematron seems to have changed in version 17 not only with the addition of Schematron Quick Fix capabilities, but also by replacing the default namespace declaration:
so that the Schematron document is now, by default, in no namespace. This isn't a problem (I can live with it or change it, as I prefer), but it makes me wonder why the default behavior was changed. Are there advantages to defaulting to no namespace, instead of to the Schematron namespace?