I'm working on minidom's DOM Level 1 compliance, targeting Python 2.6. We have some bugs involving DOM property behavior. For example, setting the nodeValue attribute of an Element is supposed to have no effect. We don't implement this.
The right way to implement these quirks is using new-style classes and properties. Right now minidom uses old-style classes and lots of hackery, and it's pretty broken. (Another example--there is an Attr._set_prefix method, but it is *not* called from __setattr__.)
Surely nobody is subclassing these classes. You don't subclass DOM interfaces--the DOM doesn't work that way. So this change should be OK. Right?