No: standardisation is easily enforced by just having two server lists, one for normal/central hosting and one for custom games where any host can register. At

No: standardisation is easily enforced by just having two server lists, one for normal/central hosting and one for custom games where any host can register. At most you might want additionally give the user the ability to blacklist servers for themselves, and that's it. The reason for banning community servers is probably mostly for combating piracy; by eliminating the ability to run on a LAN the game must always call home to be played.