What feature do you want to see added?

I have a survival server I am working on and I want to make it so when a unregistered player joins they are asked for registration after a pre-configured time like 5-10 minutes. I know that a hacker can join with their name and steal all their stuff, but what could you grind in 5-10 minutes?

Are there any alternatives?

None.

Anything else?

This will prevent players who are lazy to write a password, allowing them access to server instantly.

Adding to this, for the unregistered period of the player, it should only allow logins from IP's same as the IP used when the player first joined. This would prevent hackers from stealing their stuff in case of a accidental disconnection.