What about a feature where the asker can transfer a comment to an answer?
51469
Allow converting comments to answers
126795
Also show "Add a comment for the author" selection when deleting/voting to delete an answer
27040
Is posting someone's comment as an answer okay?
105348
What's the best way to invite a user to answer a question on Stack Overflow?
131949
Comment votes can be easily gamed by users with the association bonus
16630
Allow users to mark "accepted" answer on someone else's question?
82959
Can we have threaded comments?
111738
Could mods have "add comments to chat" to supplement "move comments to chat"?
115812
Allow locking of answers
18236
How can you get the permalink for an answer to a question?
91663
View question when answering
20118
Is there any way to favorite/bookmark an answer?
78459
Comment promoted to answer
39016
Inform new users if they can upvote an answer they accepted
9917
Reputation for comments?
1052
Subscribing to questions and comments that don't belong to you
54812
Comment upvote, undo, and then re-upvote: why not?