How can I get JSM Cloud to see an incoming email is being sent as "High Importance" (ie - that RED !) and automatically escalate the priority of the ticket to "Critical"?
This isn't supported OOTB today. Here is an earlier post that I had responded to - Service-Desk-Ticket-Set-to-High-Priority-from-Outlook-High-Priority . If you check the status on the ticket suggestion you will find that it now has a status of not being considered. Assuming that remains the case your best bet would be to consider incorporating an add-on email handler assuming that as an option.