Just a few suggestions I think it would help improve the app and how we communicate with people here:
  1. Add inactivity indicators to show if someone is away from the app or not responding to anyone at the moment.
  2. Implement a feature / status to show if users are catching up on letters. That would help a lot if it's been a while.
  3. Add a system to display average reply times and how often users check the app.
  4. Let users indicate if they reply with notifications or you'll have to wait longer.
  5. Include an "unfriend" option to reconnect without permanent blocking.
  6. Chat option addon.