In my experience with ExtJS3 and 4, there is a lot of knowledge in the community that isn't being tapped. One easy step would be to allow user contributions to the API docs, via an attached wiki system, maybe similar to what MSDN does. A little editing/policing would help cull out the "misplaced help requests" and the "angry posts", but leave Sencha with a much more robust and up-to-date documentation center than what it has now.
Or, is there something like this already but not featured on the Sencha site?
We have talked internally in the past (over a year ago) about making this exact thing happen (similar to the PHP docs) but Sencha has not made it a priority yet. Other more important things got in the way I guess.