I've got two suggestions:
1. create separate room for flex discussion (as was done already for groovy, ruby, scala)
2. not a suggestion actually... I'm playing with flex under idea 7.0.3.. refactoring and code completions are working... but I've got strange feeling that there is no autoimport feature or it doesn't work for me.. I mean this:
if I type "class Haba extends Application" idea should suggest to import mx.core.Application. it doesn't happen.
also mask imports seems not to work either ... I mean that if I type import mx.core.*; (not .Application) "extends Application" is still highlighted as an error.
I'm not a big fun of antless compilation (this would be a plus, but not so big) I'm quite happy with flex ant tasks as I would like to be able to build project w/o launching IDE... I belive that Debugging & unittesting are more valuable features...
MXML UI designer would be of great help for people who are getting started with flex, only if you have enogh resources :) ..