I just have read Hani's bile about it: http://www.jroller.com/page/fate/?anchor=idea_s_open_wtfomgbbqapi
I, too, think you should put more effort into the API and its documentation.
Make it easier to write plugins.
Come on, there are some features that could have been coded by plugin writers years before...
Why wait until you find the time to code it yourself?
If someone writes killer plugins (like Dave Griffith did),
do you think it will cause you making less money ?!
... ah, you just want to keep the fun coding limited to
the Jetbrains team, don't you? :-|