I've seen a few posts on Arqade Meta with the discussion tag. It's unclear if the discussion should occur in the answers of the post or in the comments in response to the post.
In this discussion of modded Minecraft Close Reasons there were seven responses to the post in comments, and three responses written in the answers.
In the related January Minecraft tag cleanup the two responses to the post using the answers were used to identify what tags were changed. The nine responses occurred in the comments instead. Additionally, a chat was created for this cleanup effort.
A discussion on the use of the photo widget generated six responses in the answers section and six responses to the original post using the comments feature.
What I'm getting at here is that there are very inconsistent forms of response. The use of comments makes for a cohesive, structured conversation as they're presented chronologically. Answers are practical as they allow favored opinions to float to the top of the post through the use of votes.
Is there any kind of preferred method of soliciting feedback to a "Should we do X" discussion post?