Would be nice if you could select a single viewport and Re-Link that viewport only, or select several and do same. (maybe you can and I missed it?)
Currently I save a copy of my LO file and Re-Link to another SU file...and then copy the desired viewport(s) and paste.
Most of the time I Re-Link to a saved copy of the same SU file as the client wants to see different color schemes and I find it easier to just save a copy and change textures/colors/etc. This preserves same scenes/etc. in SU and same viewports/ scales/etc. in LO.
Other times it is because the revisions get numerous enough that maintaing one SU file with the Existing/New via layers gets cumbersome and I simply save out a SU Existing File and Resort to version(s) with revisions.
Anyhow...I find myself thinking if I could just Re-Link certain viewports my life would be a bit easier.
Thanks,
Charlie