I read a bit more into Dart, its optional typing is very interesting. I might even like that if it were a change to Javascript itself.
Of course Javascript has problems, every language has problems associated with it. They all have strengths and they all have weaknesses.
From what I've seen, projects like GWT, Dart, and Coffeescript come out of communities of developers other then the web development community. GWT and comes from Java engineers as an attempt to not have to write javascript, Coffeescript comes from Ruby developers attempting to accomplish the same thing. Now Dart is another attempt by the Java community to not write Javascript.
The thing is, I never hear from the web development community that Javascript is broken, missing major features, and needs to be replaced. These are the people using Javascript every day. The people that say Javascript needs these features are people who don't use it that much.
People also used to program computers with punch-cards. Everyday. Of course they can use Javascript.
You didn't address any of his points though. Where are the great Javascript tools and IDEs? There are tons of them for languages with static typing and classical inheritance.
Here's just one tiny example: Compare how you go about refactoring code (renaming classes, functions, etc) in Javascript with the many ways that it may be done in Java or C#.
He made many points, Javascript not having great tools and IDE's is only one of them.
It's a valid one though, the Javascript IDE's out there aren't very good. However, that's a function of community support, not language quality. Personally, I don't use an IDE for javascript or RoR programming, I just use Textmate.
I use Eclipse for Java programming, and I don't think I would want to program in Java without it. Maybe it says something about the languages themselves that they require an IDE to develop in.
Actually, many people have tried to build refactoring and editing tools for JS and they always hit the same limitations. The language is just not conducive to tooling. Without a great refactoring tool, big projects become difficult.
Of course Javascript has problems, every language has problems associated with it. They all have strengths and they all have weaknesses.
From what I've seen, projects like GWT, Dart, and Coffeescript come out of communities of developers other then the web development community. GWT and comes from Java engineers as an attempt to not have to write javascript, Coffeescript comes from Ruby developers attempting to accomplish the same thing. Now Dart is another attempt by the Java community to not write Javascript.
The thing is, I never hear from the web development community that Javascript is broken, missing major features, and needs to be replaced. These are the people using Javascript every day. The people that say Javascript needs these features are people who don't use it that much.