Well not entirely, but it did slow down my growth. I have been working full time for about 4 years now. I took the first little while to get accustomed to full time work, then jumped into testing. I tested for about a year and a half, and have had my license for well over a year now. Looking back on the whole process, it is truly a disaster.
The fact that NCARB has a minimum standard that they expect a professional architect to know, yet do not produce any real study materials, is truly astounding (their joke of a little packet doesn't count in my opinion). Many people spend crazy amounts of time reading books, studying vocabulary, reading other people's notes, doing all kinds of things to learn information that most likely will never show up on the tests. That is why the people that do well on the tests often study less, because all they need to do is figure out the NCARB question game. It is a logic test no different than the SAT. You can't study the actual material on the test, so the way to be successful is to study the thought process behind their questions.
Does this process actually help you become more knowledgeable or a better architect? In my experience, absolutely not. I usually skimmed the Kaplan and Ballast books, then just studied their question structures, and never failed a multiple choice section (the site planning vignette got me once). Much of this has to do with the fact that I'm a logical person and do well on logic tests. Most creatives and designers, aka architects, are not and don't do well with this structure at all. Most of the best architects I know struggled significantly with the ARE tests, and some never even finished them (I still refer to them as architects...because...NCARB).
Now that I am done dealing with ARE testing, I have much more time at lunch and outside of work to actually further research and study the issues I am dealing with in the office, and the issues that I am actually interested in. Experience is what makes you a better architect, not the ARE. I am 100% sure that I would be a better architect today if I had not had to take the ARE (and in my personal opinion, cutting experience hours is going in the opposite direction as well).
With all of that being said, NCARB is a truly laughable organization. They are the biggest joke of a professional organization that I have ever seen, and should be treated as such. I have close friends who have taken the BAR, Medical Licensing Exams, CPA exams, etc., and none of which have had to endure half of the crap that we go through. If NCARB wants people to actually learn specific material to pass their tests, they need to produce it. Bottom line. None of this third party junk that turns the whole thing into a game and not actually a test of knowledge. What do they gain from the "secrecy" of the material that's on the test? Nothing (well maybe money...). If they want people to know certain things to become a professional, tell them what that is and let them learn it. The majority of the information I was supposed to be studying, I didn't study. Instead I studied the NCARB thought process and learned nothing, yet here I am as a licensed architect.
Congratulations NCARB, you could actually make more money by producing study materials and losing the secrecy, and you would actually help people become better architects. Instead, you are just in the way of this profession.