If javascript were any worse, it may have been sidelined entirely before it had a chance to improve, and we would be using proprietary application stacks like iOS even more heavily for client side development.
And we should keep using it in 2012, 17 years later?
Good luck displacing JS. I mean that sincerely, especially if you work in the open. Dart had a rough start but even ignoring that, I don't think it will succeed. We'll see.