In reply to AMS:
"I think it is also significant that many of the people critical of the license choice would be fans of Linux."
Well, that's correct in my case. It's hard not to be a fan given the freedom it gives you to learn and experiment, modify and redistribute. Even if you don't want to look at the kernel itself, the fact that it's Free Software means that there's lots of software projects that you can get involved with or build on to create new software.
RISC OS, as it stands today, doesn't enjoy the same amount of interest from the same sort of developers. You can lock it down to a particular architecture and impose all sorts of license conditions on developers and end users, but you have to ask whether it will make it interesting for people to develop for. If it ensures the future of RISC OS as an embedded operating system, where does it leave all the desktop users?
I think we disagree about licenses because you seem to want to support and promote an operating system (and desktop environment) while expecting relatively little in return. I find it strange, but not surprising, that people are still willing to do that. Nonetheless, it is up to Castle to choose a license that suits their needs, and these need not match those of their desktop customers.