I think that there is always learning and adaptation that can be undertaken to improve what is already there.
What struck me looking at 'Discourse' was perhaps a resemblance to 'Google Wave' -> http://googlewave.blogspot.co.uk/. Now that has been given to Apache -> http://incubator.apache.org/wave/ so perhaps there is a chance of taking ideas from both to combine forum postings into conected conversations.
Discourse is written in Ruby on rails and Google Wave in Java at the server ends so would require quite a bit of refactoring. But more so a brand new interpretation from a Moodle perspective.
Cheers,
Gareth