Google engineer here too. I completely agree with the fast edit/refresh cycle being a huge plus but that's precisely what Dartium (the build of Chromium that includes the Dart VM and ships with the Dart editor) is for.
Yes, developer workflow is one of the key points I think anyone who has looked at the Dart documentation would get. Or, better yet, even try using the language for five minutes.
As a Dart learner, thank you. Dart IDE is great. It has some rough edges, it is new, but I like that the IDE is developed along the language and the VM. It make a difference.