In v16.2, has anyone changed the portal designer primary navigation to include additional tabs?

Are you trying to add back in the Reports tab that was removed in 7.11? In that case, I would note that the functionality from the old Reports tab is fully available in the /design environment.

ultimately, I would want all my users to be in tempo or somewhere other than a designer view. Our goal is to get everyone out of the portal space but I cannot do this overnight so I need to provide them the ability to view reports in portal designer until they are trained and have everything they need in tempo.
Is there away to enable the ability to preset users with reports tab in the portal designer?

I agree that depending on your requirements the migration to Tempo may be non-trivial, but as per the release notes for 7.11, the tab has been removed. It is not intended for it to be added back.

Maybe I just don't see the correlation between Appian Designer and reports. Can you help me understand why I would send a general user to a designer interface for their reports? Assuming reports have been created for this user/area and they don't have the knowledge to create or modify anything in the system. These users I'm referring to only interact with tasks they receive or submit a workflow to engage another area.

In that case I agree, there is no need for the user to access /designer. You can expose the reports in the Reports Tab in Tempo, or in the /apps environment if you are not yet using Tempo.