Yes, I know this may be crazy, but delete the friend's system out of player servers. Or, add an option to disable it in your dashboard or something. This is because I have great ideas for one on my player server but I can't use /friend because of cubed craft's. This would make my server experience fun as I am adding separate chats for separate games. PLEASE PLEASE PLEASE!
Next, could we have the encryption feature porama has been talking about.
Finally, add a backup feature as IDuckz_ suggested. This would make player servers safe if you may have found a bug.
Thanks, Real_Josh_G!