Permanently Open Servers
As pretty much everyone knows, you can create your own server. It's free, and it's easy.
However, leaving a server results in the room becoming nonexistent, just like it was before you created it.
My suggestion is simple. A system where you could pay a certain amount of TC (it could be a subscription, or just have one large price) to create a room that would stay open, even with 0 players in it, similar to public servers. It would allow for users to create public rooms that would never be created otherwise.
For example, say you've just created a competitive mod you believe is decent, and you will pay any amount of money required to make it known. You could create your own "public" server with the mod loaded, and come and go as you please without having to leave your computer on and AFK in the room.
This can be built upon. I made this thread quickly and didn't think absolutely everything through.