Bringing this thread back up since I have found it and it is relevant to a situation I have seen.
The version I am working on is R80.10 (it is 31 January 2018 today) and the behaviour of the system seems to be the same as ChrisF described (above) in terms of 1. the copying of rules with sectional titles is not supported and 2. there is still the need to create a whole new policy package and paste rules into it in order to have a good and immediate roll back after major changes to a rule-base (single ordered layer in this case).
The scenario I have seen is that a Policy Package was deleted by an administrator (by mistake).
The Read Only (Revision View) of the Revision that contains the deleted Policy Package shows the rules as Read Only and they cannot be copied and pasted to the current session/revision.
Should I be able to or am I missing something that would allow for an easier restore of a deleted Policy Package.
One other thing:
When right clicking on a rule there obviously all the expected options (New Rule, Sectional Title, Delete, Cut etc.). Perhaps there could be some small icons in the menu (on the left hand side and in the column where the Disable tick box resides). So that, for example, next to the Delete option we see (and can then quickly identify) the red cross that is so often associated with the delete action, and the scissors icon that is so often associated with the cut action.