I agree w/ TB about earlier (or draft) script scenes and always have...if they were not filmed then they are nothing more than abandoned ideas.
Deleted scenes are quite a different thing. While some are fun time fillers, many of them add depth and background to already terrific stories/sequences. I could name quite a few and so could others, I bet.
In many cases, the only reasons they were not used in the theatrical releases are due to editing/time restraints. Especially in the case of 'The Godfather', where success was not yet guaranteed.
If the deleted scenes used in the Saga weren't 'canon', then they would not have been included by Coppola.
Apple