I don't think Dart is better. It is better in some ways, but it's not enough. You're not seeing arguments because currently people don't care. Thing is, Javasc

I don't think Dart is better. It is better in some ways, but it's not enough. You're not seeing arguments because currently people don't care. Thing is, Javascript works as a target for other languages. For example ClojureScript and Scala.js are examples of compilers targeting Javascript, amongst many others. So people that want an alternative to Javascript already have options. From a technical point of view, I think Google made a mistake in designing a new language, instead of a new VM that could be used as a more efficient target for multiple languages, because even though Google tried copying the good parts of Javascript's story, you can't beat the incumbents at their own game. And from a social perspective, Dart is seen as an attempt to fragment the web, so Google's handling of the situation was poor.