I know that there has been some assertions around the quiz being automatically graded and as it's quite complicated it does control it's own visibility of grades and feedback.
One of the issues we've been finding is that our staff have set up quizzes for students to undertake and then they want the results embargoed effectively until a specific time.
At present the mechanism that is exists is to have the quiz close and for there to be no review options for the state "after quiz close", but this doesn't really give us enough granularity.
In the scenarios we have the quiz may close (say on the Friday) but we may wish to embargo the results until the next lecture (say on the following Thursday). The only way to do this is to manually go back in on Thursday and tick the relevant review options.
I appreciate that this can be viewed as the same as manually making the grade item visible, but it's 5 ticks and a save click as opposed to 2 in the gradebook setup.
It seems that it would be "nice" to either schedule this change or some other mechanism. Other activities can leverage the hidden until feature of the grade book but I don't believe that the quiz grade items afford this due to quiz taking over control of visibility.
So I'd quite like to propose that either the hidden until feature gets moved into quiz module or is made available again in the gradebook so that it is consistent with other grade items.
If there is a way to do this so that it's optional I'd pursue that route but I don't think the quiz accessrules would allow a plugin that affects the viewing of the quiz results, only the initiating & taking of the quiz itself.
Of course allowing quiz access rules to affect the viewing of results could be an alternative route to achieve the same thing without hard-coding the logic into core (and allowing different implementations as necessary).