I think this would be better instead, same as OS ticketing, where you could have even the original/last message if you later on add another contact for approval and the new contact was not a watcher in the begining, so in that way, when you ask for approval you can integrate the original/last message as well, and of course, the canned responses as premade replies for what you need.
also, see there on the top you can see Reply to, would be handy to have this option too, where you could either reply to all watchers, or just to the ticket owner, if the ticket have multiple collaborators, but you only need to chat with the ticket owner directly.
