I love JavaScript as a language, there are some neat things in it (not the least of which is expando object, whoo), but there are much better tools than it for doing application development (even if we go no further than Flex or SilverLight, we've improved dramatically over JavaScript in terms of project management and toolchain availability). If you're worried about namespacing, then you're using the language with the intention of a real application programming language. There are other ways to get code to client in a web-accessible way that doesn't mean "AJAX everywhere!"