I won't get into the argument of whether or not this particular expansion is too pricey. They haven't actually announced how much stuff will be in it, have they? so it's kind of hard for me to judge.
I just have always found arguments about "incompleteness" strange, when applied to any game, really. I guess I just think "completeness" is kind of a weird thing to judge an RPG on. I have to wonder if people who find WFRP3 "incomplete" would say the same about, say, the nWoD core book. It's certainly playable, but the only specific "monsters" it has rules for are ghosts and there are no supernatural powers in it beyond a couple pages of numina for said ghosts. In a more extreme example, would anyone claim that Exalted is "incomplete" until there are books for every type of Exalt? (btw, my apologies if anyone reading isn't familiar with White Wolf games - they're the most well known RPGs I have high familiarity with). To be fair, I think there is a much stronger argument that the WFRP3 core is "incomplete" than, say, the Exalted core. But I think it's really a matter of expectations. If this was the first incarnation of the Warhammer IP (or the game was based on a brand new IP) I think the "incompleteness" claim would come up much less frequently. People that are familiar with previous editions, or with the world in general, though the war game or the MMO, expect (perhaps rightfully) to see certain things covered by the game, and until it does it will feel incomplete.
