That's a good way of putting it (although perhaps "everything" is too strong a word -- we don't want to build every paradigm imaginable into the language).

When in doubt regarding features, I tend to ask myself "would a next-generation browser engine need this language feature to be more secure/more maintainable/faster than current browsers?" (That's not to say that we're building the language only for a browser engine, but I think it's useful to have a target use case in mind when designing a language.)