Listening to the calling number before each voicemail message that I playback consumes a lot of time and in most cases it is of no interest since the caller is known or identifies themselves and provides their correct callback number in the message. I usually don't pay attention to that part of the playback. Time Received is typically of more interest but also is sometimes not needed and takes considerable time (i.e. robo/marketing calls. Which is 99% of my voicemail!).
How about providing a configuration option to suppress the calling number playback or select when it is played, before or after the message. Similar options could be provided for Time Received, preferably independently of Calling Number. Both are already played back when option 5 is selected after initial message playback and this should continue as a way to manually retrieve Calling Number & Time Received if they have been suppressed.