Learning a new language isn't that hard. Dart is very similar to languages like C# or Java. Dart isn't that groundbreaking different. It's an IMHO new approach to what many think should have been done a long time ago and just a few steps further than already existing technologies. Usually it's much harder to learn how to work with the provided libraries and frameworks. Those who are used to web development can easily reuse most of their knowledge and just add a little bit more each day to benefit from the new opportunities as most are used to anyway.

Exactly - this is not a radical new language. This is a language that in my opinion takes the best of JavaScript and Java, and puts them together. If you're familiar with either, Dart will take you a few hours to get into. Developers, even novices, should not be afraid to give it a spin. It will be VERY familiar.