Yes, the situation seems much better than I thought. I didn't realise Angular.dart was unrepresentative.
We've been working with the dart2js team to reduce the size and they have been making incremental improvements. AngularDart is smaller this week than last :-)
Both 170KB and 70.5KB are still pretty huge for trivial apps, though.
Great to hear! Looking forward to giving Dart and AngularDart a go.