"Aren't you just falling into the same trap riscosboss did, and ignored the earlier list of obscure additions rjek gave as examples?"
I don't think so. Just because rjek doesn't think people use these features, does not mean that they do not get used. Let us not forget all the various features of Select that have been added that rjek did not mention. Not to mention thsoe users who prefer to keep out of these types of discussions on both webistes such as Drobe and other discussions lists.
Built-in USB - only reason it is built-in is because it is Castles USB implementation. RISC OS 6 does not require this to be built into the ROM images due the drivers being provided by a third party, when they purchase a suitable addon card
Unicode - Agreed
PCI Support - There is no system that RISC OS 6 runs on that required this, therefore why include it?