Description - Requested By is the Entered By Name, the person who submits the request may not be the person that is making the request. This happens often when a project manager or admin gets emailed a request and submits on the requesters' behalf.
Why is this feature important to you - The Primary Contact is the most relevant person aside from the assignments and necessary for communication. Having this information in the header will save 2 - 3 clicks on every issue and lessen confusion for users.
How would you like the feature to work - The feature would work exactly as the "Requested By" header option
Current Behaviour - Showing Requested By and reminding teams that if they see someone from the internal team or a Workfront admin they should navigate to overview to identify the Primary Contact