I can imagine that Jetbrains had endless discussions about what to open source and what to put into the Ultimate edition
And yes, you should dump the Vistaish "Ultimate" and call it Professional or Enterprise.
My 2 cents on the Flex plugin:
Most Flex developers I know would not buy IDEA just for Flex development (and thus do not generate business for Jetbrains) because they do not want to bother with anything but Flex Builder - or are too lazy to try something better. All my fellow Java programmers use IDEA anyway - so many customers get the Flex plugin without using it. I tried all alternatives (Flex Builder, FDT and IntelliJ IDEA) - they all have features which the competition does not have, but as compared to Java IDEs they all lack strong refactoring features other than rename. I think there are enough Java developers using IDEA Flex willing to contibute to the Flex plugin to give it a real boost and put it further ahead of the competition.
Maybe there are already Flex plugin extension points which need some documentation?
Thanks and Regards,