That's a little too, um, "magical" a version of how standards get made.
In truth it's a pay-to-play sausage-making fest, with incumbents privileged against newcomers -- but at least with the Web, some 10M growing to 20M developers are the ultimate sued-to-woo power.
I'm not yet worried about Google cramming this down other browser vendors' throats. MS and Apple will only come on board when it's in a state where Mozilla is on board too, I predict. This may not happen, so don't count on anything. Do use and report usability and other bugs.
Perhaps you're right, and I merely remain wholly unconvinced, though I acquiesced in the OP that perhaps it will be necessary. Optimizability dictating language features to this extent is the tail wagging the dog. I think this would undermine the ecosystem by creating a subset that is neither Java nor JavaScript, neither safe nor dynamic; a lowest common denominator of sorts that may do more harm than good in the competition with native.
Going slightly away from the topic, which I agree with you entirely on, btw...
This is pure speculation on my part, but I wonder if a lot of the Google devs involved in JS in one way or the other just aren't that used to writing it.
It's this quote that caught my attention
Optimizability dictating language features to this extent is the tail wagging the dog.
Apologies to Java devs if this is uncharacteristic of the community, but a lot of Java devs I know seem to put performance and vm internals ahead of expressiveness.
AngularJS is another project that strikes me as being heavily Java inspired (although it's neither expressive nor performant), almost as if its authors are used to writing desktop applications in Java or C# and just wanted to port their experience to the browser.
It's as though the authors of Gmail or Google Docs are not people developing these other things.
That's what this proposal is.
You can disagree and discuss alternatives, and that's great, because that's how standards get written.