I think you kind of answered your own question… The biggest impediment to making Discourse Q&A software is that Discourse isn’t Q&A software.
If making Discourse a good Q&A platform would mean changing the underlying structure that makes Discourse a good conversation platform… then it’s not likely to happen. It’s just incongruent with what Discourse is meant to do at that point.
I don’t think anyone’s opposed to improving the existing Solved or Voting plugins. Are there specific things you’d need for those to work better for you?