Yep - I've never yet taken that career, mostly because of the morality of it; however, the one time I did attempt it, I fell at the second hurdle in Act 2.
Heart of Fire has a number of 'tough to get' careers as well. The ones that are a challenge are (Spoilers below - highlight text to read!)
Spirit Hunter
Scholar
Blood Archer
Seems like one for each path - and I would say that each of these is a strong career choice as well!
Eye of Winter's Fury is very different - it's actually difficult not to stumble on all the careers in that book! The only ones that you might miss would be Bard and Chemist. (Highlight previous gap in text to read if you don't mind potential spoilers.)