Coming from other multiplayer games like this, I think the following should be implemented very soon (definitely before the steam release!):
- Proper authentication for multiplayer to identify who connecting players really are
- It should not be possible for two players to have the same name at the same time (globally)
- If people should still be able to change their names, it must also send a unique identifier to servers
- Ability to kick or ban players from the server (using unique identifier from ^), with ban management gui
- Ability to password protect the server
- Global server list