Sometimes it's needed just to copy informations from another existing task and make a new one with slightly changed title and desc, but with same subscribers, same projects, same security, blocked by and so. What about to add an option into the right menu next the task heading?
In order to achieve the link by @mmodell easily: Task could be copied using https://phabricator.wikimedia.org/maniphest/task/create/?template=, but there should be a button to achieve this function easier.