Yes, it should be another issue.  That said, there are similar (worse, actually) problems with the py3 email package that we are moving toward addressing.  There we are planning to have dual APIs.  If you want to work on fixing nntplib similarly, that would be great.  I'm expecting there to be synergy between the two, so you might be interested in joining the effort to update the email module as well.  See http://wiki.python.org/moin/Email%20SIG for more details.  (Trying to use nntplib in py3 is how I myself wound up involved in the email effort).