Emmanuel:
Before using SH3D I used a program that had "cameras", basically the same as "viewpoints", I guess. It seems to me that you would need:

Camera or Viewpoint
[1] New - lets you choose position and orientation, and define quality settings
[2] Delete - lets you delete (from drop-down list?)
[3] Select - lets you select (from drop-down list?)

For the New part, I guess you could re-use one of the current camera-setting screens from Create photo or Create Video. The more it resembles how that works, the easier the new function can be used, and the less work you have.

You might even integrate this function in the Create photo screen: add a button Save as viewpoint and a drop-down list from which you can Select or Delete a viewpoint.

Hans