I really like Dart. I'm surprised its not getting traction faster. Its a language with few surprises, everything looks familiar and works as you'd expect without gotcha's. While it doesn't feel cutting edge like Haskell or retro on steroids like Clojure, it seems just right as a replacement for Javascript.
I really like Dart too and actually have worked on projects of multiple types (e.g. a game/simulation, parts of a web-app etc.). The just seems right thing that you mention actually resonates with me (in fact, resonated enough for me to teach students in an undergrad course that involved designing and building a web app).
That being said, traction for any new programming language is hard. A programmer's learning time is limited and most programmers would treat it as an investment. In Dart's case, the investment will make more sense if the Dart team could get the VM onto Chrome's release channel (not Dartium/Chromium as it currently stands).
I bet that's going to be a hard fought battle, but I believe this would incentivize developers to code in Dart and serve Dart2Js generated js files to other browsers (FF, IE etc.); especially because the coding/debugging experience is so much better than vanilla javascript (I am now prepared for coffeescript advocates to join the fray).
"I'm surprised its not getting traction faster" "replacement for Javascript" - doesn't work in other browsers without transpiling. Since it transpiles, it is not a true replacement. Replacing JS it is right direction nevertheless. Better idea would be integrating two major VMs into browsers: Mono and JVM, keeping them evergreen and just letting developers use any programming languages to have an actual open web instead of one we have now.
There are so many novel, cool "JS replacements" that it's easy to feel some paralysis about the whole matter. Do you go with Dart? TypeScript? Clojure? Or do you stick with regular JS and start learning a new framework (e.g. Angular)?
They're not necessarily mutually exclusive, but I think a good majority of web developers are waiting to see what unfolds before committing one way or the other.
