For the alliance that are invite only, I think it would be really nice if can let leader and elder to invite the player into your Alliance. If not, then make it to request only.
The allanice can only have 30 player, but it would be nice if we could upgrade alliance to have more player.
Or you can set up a private message for players to messages each other, instead of messaging it on the world chat. It would also be good if could add a friend’s list.