I have to maintain several portal groups with 100s of members. While I can easily populate the groups with members I cannot easily export group members to a csv (the way I imported them). This feature would close that loop and make it easier to manage groups. The commandline tool (ListUsers) is archaic and does not provide group level granularity. Currently I need to work manually through the user list on portal and check which members have left or joined. With this feature I will be able to quickly identify old and new users and update my group members on portal without too much manual intervention which will save me time and prevent mistakes. Note that I do not have access to AD groups so I cannot use that option.
This idea has been marked as a duplicate of Provide CSV / XLS download of user lists from Portal and ArcGIS Online - Please continue to share your feedback and upvotes on the "original" idea. Thank you!