I think it would be of value to have the ability to export only certain tabs. Before upgrading to TB-HCE 4, I had gone through and made a tab that match my work flow, taking bits from all of the tabs I bounce around in and organizing them into one master "Pat Data Prep" tab. When I updated to version 4, I imported my tab settings but was missing out on some of the new functions. I therefore set the ribbon back to default settings and I have just been using those since.
If we had the ability to export selected tabs and then import those, it would allow users to create custom tabs that match their workflow but still keep current with changes and improvements being made to the standard TBC tabs.