Gabriele Renzi has a good post on the future of JavaScript:  "ECMAScript 4, the fourth system syndrome".  The concept of a "fourth system syndrome" is a good one, particularly so for programming languages.  For mature programming languages, thoughtful evolution is the rule.  A revolution is best done with an entirely new language, as this serves two very important purposes:  (1) supporting existing users, many of whom presumably like the existing language, by evolving it in parallel, and (2) freeing the new language from the constraints of the old one.

This leads to a kind of punctuated equilibrium, where there are significant periods of steady evolution in existing languages, punctuated by more rapid but discontinuous change driven by new languages.  The latter doesn't happen very often, and it is interesting to look at history and consider the conditions or circumstances that favor the creation of new languages.

The ES4 proposal is publicly available.  Our JScript team is one of the participants in the ECMA working group, and is very interested in feedback from JavaScript developers on the future of the language.