It would be a small usability improvement if ElementTree's XPath support also supported the != (not-equals) operator.
I am specifically mentioning only != and not >/</... because != can be defined as the opposite of =, whereas other operators appear to run into questions of what to do with coercion of strings to numbers, etc.  (I guess that depends on the version of XPath, which may be a question we want to avoid for now.)