I’ll admit that, documentary is not my main focus.But I’ve been shooting with the 7D and using the H4N zoom mic for audio on short documentary work recently and I find, despite the issues you mentioned there are also some advantages. For one, it pretty much forces you to work with a sound person. I haven’t tried operating both the zoom and the 7D all by myself except when I am doing separate interviews. But if you have a good sound person working with you it can be very freeing and you can get much better audio than if your mic is always running to the camera.
Recently we did a shoot where my sound guy was capturing audio from 3 different locations within the scene. All I had to worry about was what to focus on for picture. I also didn’t have to worry about cutting and missing something because there would doubtless be audio there for me in the edit stage that would cover anything I may have missed. Of course you have to be willing to synch everything in post.
The main problem I have with the 7D is the need to give the camera a rest when the overheating light comes on. Oh, and using the loupe with the LCD screen is a pain as well. As is pulling focus when using a really shallow depth of field. But the HVX can’t give you that dof in low light anyway and low light seems to be unavoidable in some situations.
I have worked a bunch with the HVX prior to using the 7D and I wouldn’t trade back even with the limitations.
But I think it will come down to what you need for your own style and approach to shooting.
Hope that helps!
Miriam
https://www.vimeo.com/movingstudio