That's as close as you get to keeping your existing workflow and maintaining your assets. It's really close IMHO and works well. Also there's some scripts that can translate As3->Haxe and take care of 95% of the work of porting the code, and then OpenFL has the same API as flash does so your API calls are all the same.
Alternatively FLUMP can be used if you just want to export assets and use a totally different framework:
http://threerings.github.io/flump/