[Bobo]

I'll just say that the last two posts do hit the mark, at least up to a point.

1. Usability:
Well, 5th edition has seen great improvements in the organization department, compared to older editions of the rulebook, and I'm not sure how the organization of the GPC could have been improved without going all the way to fully annotated margins and referenced text, like Ptolus did.
Certainly it requires quite a bit of work and lots (lots!) of improv to actually run this; Greg Stafford has been quoted as saying something to the effect that you'd have to add 40% of improv and adaptive work to 60% of prepared stuff.
But that's one reason I'm looking forward to an actual playtest review, as has been promised (see above).

2. Regarding my strange desire for MASSIVE VOLUMES:
Sorry, that's just me. Partly a not-quite-serious way of expressing "how can anybody play Pendragon and not buy this book!!", partly reflecting the fact that the rulebook does not provide enough stuff for the later periods, and partly, well... it would feel right to me. I like that feeling of solid heaviness, that weighty promise of a big, fat book.
But of course you're completely right. Having two separate books is totally reasonable and obviosly the right thing to do.
Still, it would have been nice... and add more stuff from the nobles' sourcebook and older editions, while you're at it, will you? (Off fighting the windmills)