I doubt is too thin and if so minimally so. A MacBook Pro 14 inch is 15.6 mm when closed down and that includes the screen if I understand the drawings correctly. Subtract the screen, say 3 mm, the height of the body is 12.6 mm. The body of the 24 iMac is 11.5 mm. I think the current iMac should be able to have both a Pro and a Max if Apple wanted as the chin is more isolated from other components than in an MBP. A 1-2 mm increased body thickness of the iMac would be negligible and would not make it less attractive design wise.