IntelliJ IDEA for Flex, even v9M1 ("Maia"), doesn't quite work properly :( You can see for yourself: http://www.jetbrains.com/idea/nextversion/ It's been a while, but the issues remain. Maia seems stalled.
A free policy for open source projects would speed adoption of any IDE; also a free student policy, but this issue is not related to the choice of O/S. Here is the Flex Builder student policy: https://freeriatools.adobe.com/flex/ Another idea for speeding adoption would be to get FDT placed into the Ubuntu commercial source repositories, like {feisty,gutsy,hardy,intrepid,jaunty,karmic,lucid}-commercial. See https://help.ubuntu.com/community/Repositories/Ubuntu $700 is fairly steep for individuals and small businesses, which is why the competition (Flex Builder) has an intermediate price point. FDT would need to carve out features differently, however. The marketing story for IDEs is always productivity. $700 would be perceived to be good value by enterprises and hard-core Flex developers if productivity gains justified the expense. If your bill rate is third-world ($15/hr) then productivity is not an issue. If your bill rate is enterprise level ($125-200/hr) then productivity is very important. The developers of successful open source products are very good, and they are often/usually employed by large companies. A product offering that addressed open source projects would allow these star developers to become familiar with FDT, and if they liked the IDE they would spread adoption throughout their (wide) circle of influence. I hope that a 64 bit version of FDT for Linux would be the goal. A visual design surface is not important, just the basics of an IDE: edit, compile, debug, unit test. Strong refactoring features could be restricted to the higher price point of a tiered product offering. Mike