1) Properly package and add "batteries" for a server side version of Dart. Pay some team to write a proper and complete Rails/Django or at least Flask level framework -- and document it.
2) Make a Google version of node.js using Dart instead of v8.
3) Even better, merge (1) and (2) for a serve side framework with both good syncrhonous (e.g Django like) and async (e.g Node like) story.
4) Support Dart as a first tier development language for Android.