> JavaScript has the classic benefits of an incumbent technology. Programmers are familiar with it...

This is only from my own experience but I'm consistently blown away by how little people actually know of JavaScript. Between interviews and looking at samples attached to jQuery Mobile issues all day I get the impression that most people don't know how to use the prototype system at all and generally organize their code as a series of jQuery event bindings.

While this isn't necessarily and endorsement of Dart, I welcome anything that can provide/encourage well-known and sane code reuse patterns.