steelpillow: "You could be right about the GPL vs. Castle license."
That's certainly something which could really torpedo any larger scale development. If you can't combine LGPL/GPL-licensed code with the "in due course" licence of RISC OS "Open", then everyone will be looking around for permissively licensed code or writing stuff from scratch.
steelpillow: "The GPL2 vs. GPL3 issue is shaping up to further muddy the waters - GPL3 is very much about preventing hardware lockdown (Tivoisation) of software in embedded systems, and so is pretty much designed to be incompatible with licenses like Castle's. If the Linux community stick with GPL2, as seems likely, the applications communities (especially for hardware drivers) may do so too and the GPL3-specific problems may not in practice matter to us."
The GPL in its current form already affects the announced developments, as mrchocky pointed out. What the GPL 3 seeks to achieve is the continued guarantee of the various rights described in its predecessor, doing so by explicitly forbidding any violation of the spirit of the licence either by technical means or by the use of other legal instruments to distort the application of copyright law.
Think of the GPL 3 as the GPL 2 without the loopholes. Unlike the vocal Linux kernel developer minority who don't seem to understand this, I predict that the GPL 3 will be immensely successful, not least because it will incorporate compatibility with various Apache licences and other open source licences which are currently technically incompatible with the FSF licences.