It's pretty damn concise and a far sight from Java. It's more concise in many cases than JavaScript (and only more verbose around things like type coercion where being explicit is a much safer choice). I admit though, that Dart is more verbose than Perl :)
C-style syntax doesn't have to mean verbose when you have features like short lambdas, optional types, string interpolation, operator overriding, getters and setters, setting instance vars directly from constructor parameters, fewer keywords, mixins, etc. C-style syntax also makes the language pretty much instantly readable, and if you're targeting web developers, being familiar to JavaScript, Java, C#, and ActionScript, is really important.
Honestly, Dart is the most readable language I've used, and that includes many years writing Python.
[disclaimer: I work on the Dart team]
Nobody is asking you to make everyone happy. You could have made (and still have the opportunity to make) dart look like any modern web language - coffeescript, or Python, or ruby, and you'd have both users and a measurable impact on web development.