There have been way more king of the hill levels than that. For example, I made one in 1999. Thing is, you can't just 'own' popular gametypes like that. Can people 'own' team battle? Or test levels?

You can't copyright ideas like this, btw. People are free to use all ideas. If you don't want this, you''ll have to look for patents, those protect ideas, not copyright, which I believe protects you from people copying your work.