FWIW, I was very leery of the Complete Warrior book when it was first announced. I do like the book (since it updates some PrCs, as well as provide a few other options & touch base on other classes rather than just warriors), but I'm still leery about the concept overall.
For one, I'm upset that they didn't just upgrade material they already had out--the Samurai is the main case in point. The Rokugan elements/titles could have been removed, & the class could have been presented as is. Instead, a whole new class was presented, which is very focused & specific in its abilities with little flexibility (in a way, like the 3.0 Ranger).
Also, I'm cocerned that, even though classes & races are being grouped together in books, they're still going to be a lot of books put out. I honestly think that there doesn't need to be race books, since races can select any class now--any racial PrCs, feats, gear, etc., could be placed in the appropriate class splatbook.
If Complete Warrior was any indication, each one of these books (or the class books, at least--I hope) may provide a few new core classes, a bunch of PrCs (updated & maybe new ones), some new feats, new equipment, new spells, new domains, and some other info. The race splatbooks may pretty much the same thing, sans the new core classes (or at least I hope so--I'd hate to have to look up a core class in the dwarf/gnome book for a human or elf PC playing it).
Also, I'd prefer it if a lot of this resource info was gathered up & released in a few good-sized hardbacks instead of the current thin hardback releases; or at the very least, a moderately-sized paperback.
I'd really like to avoid the days of multiple shelves of sourcebooks (ala 2nd ed.). A few sourcebooks can't hurt, but I'd prefer having a lot of the info contained in a moderately small set of books rather than scattered about through various volumes.