I personally believe that cockpit video recorders can only enhance safety.
Regarding crew privacy this needs to be protected in that anything of a clearly personal nature (such as picking one's nose [which was mentioned] etc.) remains private upon pain of penalty payable by whoever makes public the breach of privacy.
When it comes to collecting cockpit data in the form of video footage related to an incident I believe there should be no contest, this data will, I am certain, prove invaluable.