You know, I remember that when 3.5 was still in development, and everyone was wondering how big the revision would be, WotC kept claiming that it wasn't a very big deal; you'd still be able to use all your old D&D stuff with little to no problems. Yet, now they're coming out with an updated splatbook. There are two reasons to revise them:
(1) Errata a class/spell/whatever. This should be done, FOR FREE, online. Though of course we know how long it takes errata to appear on the website, and how incomplete it usually is...
(2) "Update" a class to 3.5. By and large, this is minor stuff, like changing "Wilderness Lore" to "Survival" in their prerequisites. Either WotC lied to us about how easy conversion would be, or they're trying to sell us a product that "fixes" only incredibly minor points. You can "update" most classes to 3.5 in about ten seconds. That's a very good work-to-pagecount ratio from their perspective.
Either way, I don't think this makes WotC look good.