The exception is the OXO Good Grips teakettle, designed by the New York firm Smart Design and introduced last year. It is part of a line of products intended to be usable by people with arthritis or hand injuries, as well as by those without disabilities. It is the ultimate answer to Sapper's kettle, because its form was generated by the desire to make it extremely difficult for users to burn their fingers.
Though it lacks the simple, geometric form of Sapper's pot and those of many of its competitors, it is unified in a subtler way. Its complex curves suggest that it was sculpted rather than drawn. You can think of it as two intersecting incomplete egg shapes, one of which is the body of the pot and the handle of its lid and the other of which is the protective collar. The lines of the handle and other elements derive from these implicit shapes. (It doesn't photograph well; it is one of those rare products that looks better than its picture on the box.)
When I first saw the OXO kettle, I resisted it. That big black steam guard looked so ostentatiously foolproof that I feared it would be clumsy, like a bicycle with training wheels. But as I handled it, used it, and carefully examined how it worked, it started to look better and better. This is indeed progress, both aesthetically and functionally--even though all it does is boil water.