I've noticed recently that when I pitch left or right the gimbal does not adjust resulting in, well, pitchy video.  I recalibrated the IMU and compass to no avail.  I don't see any physical cause either.

Any thoughts on remedy?

Do you mean when you move the gimbal wheel or when you want to control the gimbal from the app?

have you got it Follow mode or FPV ?

Hi there, just to verify, you want to adjust the gimbal by the RC but the gimbal does not respond, besides, the gimbal is shaky, right? Please try to refresh the firmware for the drone and RC.
If the issue persists, may I know if the drone crashed before? If yes, you might need to send the drone in for diagnosis.
Please contact our support for a further help: http://www.dji.com/support