Adobe Flex (now Adobe Flash builder) is a really nice solution (framework + editor) but there are some features i’m missing:

• Multithreading: when loading some CPU intensive data the UI freezes; there are some threading-like-managing solutions available but no one works really well (the new version of AIR will fix this allowing to call native code).
• Eclipse editor smaller memory footprint (some times it grows to over 400MB);
• Faster Design Mode: too slow and why there is,  some times, the need to refresh the view and it isn’t done automatically?
• In the outline window (thw one which shows the structure tree) the possibility to do drag and drop;
• Code obfuscation: it’ a mess that is so easy to read and copy all the software code without any pain; you have to buy an external encrypter or try an hand made solution.
• Image Drag And Drop (with request to link it or embed);
• Image auto-updated when the file is changed (ie replacing with a new version), because the only two ways to force this is to clean and rebuild the entire project or to change a letter in the source filename of the image and restore it (ie: bear.png -> be.pn -> be.png)

The the use of Eclipse as developing platform is quite useless: it’s heavy, slow, and with a big memory footprint: why use a Mammoth like that if a Flex user will use only Flex features and wont access all the Eclipse features available (I prefer to use a separate Eclipse to avoid problems, which is always updated while Flex version won’t update to latest Eclipse patches). An AIR application wont’ be better now that AIR has reached a nice working version?;

After some hours of working with Adobe Flex/Flash Builder  the garbage collector isn’t able to free all the resources, the last time i checked it reached after I asked for a garbace collector operation it ended with 560MB (this means no way to decrease more resources without closing the application).