They did that in Black Ops. And typically every game that has dedicated servers have some people who setup vanilla servers. They aren't all configured radically different.
Keep in mind though, if there are servers packed with only a couple maps in rotation, it's obvious that this is what most people want. That's the free market and it's fine with me.
If lots wanted vanilla servers in that case, it would be easy to rent a server, ask for donations and/or sell reserved slots. You'd make a pretty penny or at least have the server pay for itself.