Front-facing cam: Don't we have enough cameras in our house already? When I want a picture, I get out the digital cameraor my iPhone. This thing is suppose to work with the iPhonenot replace it. The decision to leave the camera out is a product positioning one.
Rear-facing cam (video conference). Not practical. You would have to hold the iPad at the exact angle needed during the whole call. You wouldn't be able to type anything. Plus there would be lots of shaking.
Really, the ergonomics escape me...needs a stand, proper orientation, etc....with a phone, it's a whole lot less tiring to aim and shoot...