for prolonged video chat it would be awkward because you'd be shifting around and making the image a blur for the other person.
Unlike a desktop or laptop that is stationary when being used.
I would like a rear facing camera on the iPad....not because its needed or that I would really use it a lot...but because I think it would be an easy upgrade that people would like to have.
I wonder how much weight would be added to the iPad with 2 cameras in it?
More than likely, when doing long video chats, the iPad will be propped up on something or standing in one of the third party cases. It really won't be any worse than skyping from your laptop.