When editing the content of an email, include functionality to copy content from another email. Example: "copy from email". This would allow the user to select an email from any campaign and copy in the same content that would be shown when you opened the Edit Content on that given email. This gives users a shortcut to duplicating email content anywhere in the system - record emails, new autoresponders, or new campaigns - without having to address the nuances in code surrounding each type of campaign