We’re in a multi-browser market. Competitors try (some harder than others, pace Alex Russell’s latest blog post) to work together in standards bodies. This does not necessarily mean everything takes too long (Dart didn’t take a month or a year — it has been going longer than that, in secret).
Dart goes the wrong way and is likely to bounce off other browsers. It is therefore anti-open-web in my book. “The end justifies the means” slaves will say “but but but it’ll eventually force things to get better”. Maybe it will, but at high cost. More likely, it won’t, and we’ll have two problems (Dart and JS).
Honestly, I am a little sick of the hubris that accompanies decisions like this. I’ve explained my admiration for Mozilla repeatedly before as an increasingly necessary counterbalance to Google’s now established pattern of eschewing community developed open standards in favor of its own efforts. Chrome instead of Firefox, Web-M instead of Theora, Plus instead of a federated social network approach using ActivityStreams, OStatus, etc.
In the interest of disclosure, and fairness, I collaborate daily with folks at Google. They do much that is needful and even admirable. In this one area, however, I think there needs to be more forcefully and clearly asked questions each succesive time Google charts its own way, often at the expense of the open web community.