REALLY block a JID
When you block + delete someone, he can still "spam" you with adding requests ("jid@server.org wants to blabla, would you let him talk to you ?"), it could be great to refuse EVERY request/message/spam/anything from a particular JID (even the adding request) (yes, notifixious is a BIG SHIT :()
A list of unauthorized/authorized people would be great, to manage these people.