I wouldn't think that PowerPC is ill suited for reasonably low power designs. It is a RISC chip after all. And up to and including the G4, they ran very well in

I wouldn't think that PowerPC is ill suited for reasonably low power designs. It is a RISC chip after all. And up to and including the G4, they ran very well in the Apple laptops. Only the IBM-made G5 was a very hot beast, perhaps because it pushed the cpu frequency beyond the comfort zone for its process in the attempt to keep up with Intel. But a fresh design with a modern process could yield very low power and still well performing chips. Even the Itanium, which had a reputation for being power-hungry probably would be efficient enough to be used in a smart phone, if ported to the TSMC 7nm technology.