I'm sure you're right about how it feels, but "feeling like a step backwards" is normal for learning a new language since there's a learning curve. It seems hard to say if it's actually worse? You didn't start out knowing what all the built-in JavaScript functions were, right?

If you know you want to use Dart's HttpRequest class, you can just type it and a good editor will add the import for you. But people don't start out knowing what to type.