In the main ticket view, under client, there is an option (envelope icon) where you can send the client an email (using your own email software).
It would be great if this link could be associated with the ticket you are referring to. So the idea would be you select the envelope icon to email the client, they receive our email (which would be a question, quick statement, etc... as it would look in am email), and at the same time, are able to reply back to the email, with both the initial email and reply being saved to the ticket itself.
Normally when you're going to email the client, it's usually a question or an update about the ticket, so having that from the main screen would be very efficient and helpful.