Maybe AmigaOS should focus on the ARM cored platform. Intel will be dominated by Windows, with Linux making strides every day.
Something like AmigaOS with a really flexible GUI that can cope with really small / unusual screens and other output devices. Something along the lines of Contiki (
http://en.wikipedia.org/wiki/Contiki )
That would avoid the need for solving the memory management code and would capitalise on the strength of Amiga, keeping it simple.