That's not the only problem Dart is trying to solve. Productivity and the ability to build good tools for the language are huge factors in Dart's design. That'

That's not the only problem Dart is trying to solve. Productivity and the ability to build good tools for the language are huge factors in Dart's design. That's why it has libraries, type annotations, a declarative top-level structure, and some of the reason for closed objects. Good tools for Dart are _much_ easier to write than tools for a very dynamic language.