The email integration allows for setting the importance of a task, but it can't be done with web-based email providers that don't support the "priority" tags (such as Gmail). Although this functionality is commonly available in mail applications like outlook and thunderbird, it is hit and miss for browser-based mail management.
It would be helpful to be able to set the importance of a task via a subject line parameter as well. This would make this functionality available to everyone rather than just outlook users.
This would be highly useful for me as I'm trying to push updates to certain tasks from another system via a trigger and I can't set the Importance since the mechanism to send the update doesn't support adding a priority on the message.