"Dart is not a standard, it's not controlled or directed by any open body"
You say that like it is a bad thing. I don't think it is.
Standardizing technologies is great once they are mature and are already accepted as the obvious de-facto standard, but trying to push real change through standards bodies results in exactly the sort of morass that JavaScript has been stuck in and which makes Dart a refreshing attempt at change.
Yeah, yeah, the great new version of JavaScript will be here next year, same as it has been going to be here next year for the past 10 years.
When it comes to making real progress you almost always need to buck the standards and drag the world kicking and screaming into a better future and then let the standards bodies figure out how to fit things in to their world later on. I'm continually shocked there are so many people in this industry that don't see this even though the proof for it is everywhere.
I'm not sure Dart really is the better future we need in a client-side language as there is still a ton more work to be done (the technology is far less baked than I expected it would be, even though it is only a preview release), but I applaud Google for trying and I'd suggest other players trying to sabotage their efforts should redirect their own efforts into something even better than Dart. Win on the merits of the technology, not on slavish devotion to existing standards. With increased competition everybody wins, especially if everyone uses an OSS model as permissive as Google is with Dart, and maintains JavaScript as a legacy lingua franca.