I am probably about to be flamed by people who write test questions for the NCLEX in their state, but here goes....
gpip, to be honest, I never felt that the NCLEX exam (and I took the WHOLE THING in 1988, before they were computerized) was any sort of realistic assessment of my nursing knowledge anyway and, to tell you the truth, I've never met anyone else who feels so either. There were some truly bizarre and off-topic questions that literally made me laugh out loud (okay, at least chuckle) during the exam and think, "Okay, what freak wrote THIS one, and what were they on at the time?"
As had been said before in previous threads about the NCLEX, it is mainly a test to see how well you take tests. At its best, it is a test to see how well you can figure out what you don't know by extrapolating from what you do. By way of contrast, when I took the CCRN exam, I felt it was an extremely thorough and difficult, but fair, test of my critical care knowledge. And friends of mine who are CNRN's (neuroscience)as well as CCRN's said that the CNRN test was much harder than even the CCRN exam, and exhaustively comprehensive.
Now, I'm not saying that the NCLEX should be so hard that very few people can pass it. But I do believe that mine, anyway, could've been much better written, more comprehensive and more relevant.
To answer your question, though, since I've never considered, or known anyone who considered the NCLEX to be the be-all and end-all of evaluating nursing knowledge (I think nursing school exams and clinicals are much better for that), I don't think it makes much difference whether it's 75 questions or 280.