I think this sums it up really. People make mistakes and make insecure software. Whatever language it is. I fail to see how swapping out js for anything else would solve anything. It's all pretty moot also, since it'd never happen.
The JSON attack again, isn't any inherent insecurity in the language, just in the way it is used within browsers.
Lets improve browser security rather than focusing on a language which has pretty much nothing to do with security issues. None of the examples you give had anything to do with the core javascript language. They were all about how it is used in the context of browsers.
Just to get this straight, one of your arguments is that since some browsers apparently execute the javascript inside css "url('javascript:...", the solution is to change javascript for some other language? Do you understand how ridiculous that seems?