PPC is the great weight hanging over AmigaOS, it needs to change course, and fast. Raspberry PI has just hit 5 million units sold, ARM is where AmigaOS needs to go. As already stated Risc OS is making quite a comeback because of ARM boards, I think AmigaOS would sell quite a few copies for the ARM architecture.
And "please no", lets not put any Apple or Linux similarities in to AmigaOS. If you want Apple or Linux, then use those platforms.