Yes, this didn’t seem to be mentioned as part of the revamped notifications system, but would seem logical to include. And I would like to get notification of any change to the evidence in the observation – addition, deletion, etc.
Changing back to “Needs ID” could be problematic, since that status is calculated from existing identifications, Data Quality Assessment parameters, etc. How would the system temporarily ignore those factors, and decide when to stop ignoring them again? About the only way I can imagine would be to automatically withdraw all but the first ID on the observation – and that could come with its own problems.