Stephen Hackett, 512 Pixels:

However, the screen itself also changed rather drastically. The Retina display isn’t covered with as thick of glass as non-Retina machines...If Apple moved to thinner, adhesive-stuck glass on the iMac, I don’t see how the current design would continue to work.

Great insight. Thinner glass is something I had not considered.

Before adding the iSight camera, these iMacs opened from the back, as opposed to getting to the internals by removing the display. Would Apple go back to that design? I know lots of technicians who would welcome it.

I would love to see an iMac where you could access the hard drive without suction cups. Being able to replace the hard drive, the part most likely to fail, is one reason I chose a Macbook Pro over an iMac.

But I don't see them doing that. When they redesign the iMac, whether it's a professional model or not, I think they're going to try to make it as thin as possible. User-serviceable parts would hinder that.