I'm not sure if this would be within the scope of this tool but it would be interesting to have a similar button to the "Reply" one with "Edit" for each specific reply in a conversation, basically treating them as specific sections in an article. The reason I say this is because there are a lot of times in which I want to be able to edit my last comment because of a typo or another minor change and for that basically I have to scroll up to the top, press edit for the whole section, scroll back to the bottom again... In long conversations it gets really tiring.
I believe that the less people have to interact with the source code of conversations, the better it would be, especially for new users. Right now this tool almost completely removes the need for that kind of interaction. Fixing typos and similar changes though force you to start editing the whole section through source code so... (Maybe this kind of functionality could be provided only on the last answer.)