I would shorten (or remove entirely) the text that appears on the response form: "(Response will reference original comment. Signature not required.) ":
Signature not required is unnecessary as people can preview their response, which includes a signature
Response will reference original comment: displaying a backlink from the thanks message should be sufficient to allow people to find their response. The link should be added to the thanks message itself, even if it's only for a few seconds, it's kind of annoying that I have to wait a few seconds to find the direct link to the user talk page.
Should we say "Send response ->" or just "Submit"? Note: we say "Send WikiLove", I personally don't like it but at least that's consistent
The color of the text/border of the Preview/Submit buttons is inconsistent with WikiLove. Also WikiLove displays a magnifying glass icon on the Preview button
Consider displaying relative instead of absolute response times:
If we care about the absolute time of the response, than we should leave it as is
If we care about the relative time of the response (and experiment to see if this leads to some positive or negative game mechanics), then we should change it to "User X responded N seconds after it was posted". The reason why I mention this is that if we increase the number of requests we collect (which is going to happen after we introduce the bubble) we should have an easy way for people to identify the oldest, unresponded requests.
If the responder has a registered email address, add the ability to send a notification of the response by email (e.g. [x] cc me on this response). This will allow the two users to interact off-wiki in case the new user doesn't understand how to return to the wiki. Note that there should be language suggesting that the responder's email address will be disclosed to the new user if the option is selected.
Unclutter the UI
Can we display the hide feedback/respond/permalink links only on hovering? WIth the exception of the "responded" link they don't need to show up unless a user wants to zoom in and take any action on a post. To simplify the work of the response team, we could also change the shade of background of items that have been addressed.