Currently, if a Case and a Ticket are Linked, you can only email from the Case to the Ticket (and vice versa), as emailing from the Action only becomes an option after this email chain has started.
It would be ideal to be able to email from the Actions to the Linked Ticket as this is what users are picking up and working from, not the case.
As well, when emailing from the Ticket, it would be great to have the option to email to individual Actions within the Case (I.e a list of open actions are present when selecting the work item to share the email with).