Spriteman: A very interesting question and a very valid historical comparison. But we shouldn't look at history with rose-tinted glasses.
You compare the Iyonix launch (as compared with the previous top end system) with the A5000 launch (as compared with the previous - effective - top end system).
Remember that when the Risc PC was launched it had a 30MHz ARM610 CPU, with no FPA. In the previous generation of hardware you could have a 33MHz ARM3 or a 25MHz ARM3 with FPA. That's not to say the Risc PC was a bad move (in fact it was a great move), it's just that in one respect it hadn't really moved on.
In addition, you also ignore the fact that the original Risc PC did *not* have 16-bit sound.
I've rambled extensively elsewhere about how wonderful the Risc PC is, so let's avoid that here. Suffice to say that it was a major step forward in some areas, but less so in others. I've put up with people at user groups lecturing me for 20 minutes at a time about how stupid Acorn were not to separate video and other functions onto separate, cheap, cards.
Looking at the other side of the comparison, the Iyonix compared to the Risc PC hasn't even kept the "maximum" CPU speed the same. And it adds USB and, in particular, PCI. In some areas it could have done more - but changing *everything* at once is dangerous and foolish.
Everyone needs their own definition of what "can't sensibly" be done.
Maybe Castle have foolishly left out opportunities to tick boxes for things that are just impossible on the Risc PC; preferring to move forwards on some of the most important things like the ability to use newer processors and hardware independence (graphics in particular).
If so, it's less exciting, but we should thank them for it anyway.