The quick reply button is nice as it opens your mail program and creates a new message for you but often you just want to send the message in the mail grid to someone and don't need to edit or comment.
Adding a button that would fetch the entire message from the server and then redirect it to another account would be handy. The key thing is for it to fetch and redirect the entire message. Something that worked in a manner similar to the Thunderbird redirect extension.
https://addons.mozilla.org/en-US/thunderbird/addon/550
