The perl-qotw list (as opposed to perl-qotw-discuss) only gets the quizzes and summaries;
there would be no need to forward perlmonks postings to the list. Having the
discussions here and on the -discuss list be completely separate is, I think, a necessary
drawback for the reasons you list.
If the discussion is completely separate, then, unless the person running the current quiz happens to frequent perlmonks as well, the summaries would not discuss anything that was
discussed here.