"Moving away from the desktop (to tablet or sub-notebook) and more into STB/phones seems to be the best way for RISC OS (if we must stick to ARM) to go."
I agree that niche platforms should be the goal for RISCOS development. I've often said that RISC OS is settings itself up for failure when it tries to be a 'Windows beater'.
I'd disagree about the A3010 being especially good value though. I seem to remember that it was about 100 pounds more expensive than the Amiga 1200. The PC might have seemed a bit more expensive but when you factor in the monitor and the harddrive and maybe 16bit audio IO and a NIC, the PC was probably less expensive overall thanks to cut throat mass market economics.
Speed wise, the ARM250 chipset was only a 50% improvement over the 1987 hardware.