I would like to see a very simple messaging function between users, both point-to-point and hierarchically (for admin→user group broadcasts). The intention is to allow in-app-related messages for user-to-user sharing and and admin awareness & control of subordinate user groups.
At the most simple level, the messages would be simple text, plain fonts, without graphics or sound. The messaging function would provide users with options akin to the most simple of email services: read, mark unread, delete, reply, reply all (for admins only), pin to top/unpin. Auto delete after 30 days, no archive. Admin gets to send messages to all subordinate users, and pin-to-top their messages for all users, admin gets optional read receipt tick-mark (or other low-bandwidth usage notification) from users. PC-to-mobile linked accounts get an in-app notification that matches user's mobile app notification preferences. Admins get to access user accounts for shared access files only. There is a "Messages" menu item on the left side (below Security Dashboard) and at the top (next to Shared with Me).
Maybe for a more advanced service, in addition to the above, users get a one-deep folder system with Admin always at the top (if applicable). Admin gets more options like mobile app notifications of users not reading messages, user problems with logins with a optional threshold (like three incorrect login attempts, etc.), a 2-deep folder tree system, and alerts of possible user account intrusions. Users and Admins can send screenshots of error messages. Admins get an option to paste a warning or reminder splash screen that appears at subordinate user login that can be a one-time viewed post, time-limited post (appears for each login for 5 business days, etc.), or login-limited post (5x logins, etc.).