As the title suggests, some kind of NAT punchtrough system would be good for Terasology and DestinationSol. This would allow basically anyone to host a server, even without a static ip address or with their isp blocking connections to them, and players would be able to for example host a private server if they want to play with just their friends, or a public one, if they want. This would work by instead of clients sending connection requests directly to a game server's ip, the server would look up it's external ip and send that to an external server, which lists the available servers to the client. Then as the client connects, they send a connection request to the external server, which then relays the request to the actual game server. For a more detailed and better explanation see this Factorio blog post.