Admins need to simply break their addiction to these mods and host normal servers. Are they afraid that rcon alone won't allow them full control of their servers?
I doubt most admins know how to remote administrate (it's a beautiful tool, learn it) through the use of rcon. That or they don't know it's an actual feature.
rcon is such a powerful tool, but I think it's use has diminished in the Quake 3 engine. The early stages of admin mod for games like CS didn't have the slapping/teleporting/stack abuse, it was pretty much a database of people's WONIDs to kick/ban at will so people wouldn't mess with server settings.