Enterprisey's "reply-link" script at english wikipedia allows md to see and edit the edit summary when replying. By default it says "Replying to USERNAME" where the username is a link,. seeing that I can add another user to ping in the edit summary + also i can summarise my reply in 2-3 words to make my edit easier to find in history . It seems this reply tool does not use the edit summary at all?
Topic on Talk:Talk pages project/Replying
Does not show or offer to change the edit summary
I agree that the default summary "→Section: Reply" is not useful. But the "Replying to USERNAME" is also not useful: you reply to a comment, in context of the discussion, your comment is addressed to all users participating or just reading the discussion.
The most important is the ability to summarise the reply in a few words.