Uhhhh TC39 meets bi-monthly. If you meant ECMASCRIPT 6, it's targeting finalization next month. Furthermore, future releases are set to be much, much faster than previous ones.
I would be somewhat happy if ES6 was finalized next month, but if it slipped (again) I would not be surprised. You'll also have to forgive me if I am skeptical of claims about the increased speed of future standards. The burden is on TC39 to prove this to me and I reserve the right be skeptical based on prior evidence until I see otherwise.
Also think if anything or anyone is going to make a change it would have to be Google. Can't image a small company out there coming up with a new browser with a new language. It would have to come in Firefox or Chrome. So I am excited for Dart.
I honestly don't even care if Dart doesn't take off, maybe clojurescript or something similar will instead. But my god something needs to happen in this space because the JS standards body has spent almost 2 decades aggresively doing nothing about the many gaping, egregious flaws in Javascript. Its 2013 and we don't have lexical scoping as standard, but hey let's dick around in committee for another year packing in generators, etc, etc, etc.
I would honestly put a lot more weight in Brenden Eich's words if the state of Javascript and web dev wasn't so absolutely dismal and if he wasn't trying to crap on a project actually working to do something about it.