if you're going to have any dialog, forget using the cam mic, it's worthless. But for just getting ambient sound, it's ok. I use a shotgun mic all the time though.
In pretty much any circumstance where you're recording people talking, you should have the mic as close to them as possible and not on the camera, so it won't really be an issue.
If there was another addition they could make to the 200a/170 that would really make me happy, it would be to add another audio input that would allow you to record from that input rather than the on board mics.
Even if it was just a stereo 1/8" jack, it would be nice to send a pair of wireless lavs to those channels and still have 2 XLR inputs for boom.