I think this would be appreciated by server admins, especially those who have multiple servers.
To redirect from server A to server B, server A had to know server B's adminpass, in order to be able to redirect there. (Can be used to check if server B is full, if yes, then do not redirect.)
Would be nice when having multiple servers. Server A is full, redirect player to B.
If server B is empty, and server A has empty slots, ask player if he wants to be redirected to another server.
Also /redirectall <server_alias> would redirect all players to server_alias, where server alias could be determined in server_aliases.txt. The structure would be following:
[ALIAS_NAME]
IP=server_ip
Port=server_port
Adminpassword=server_admin_password
Discuss.