I was in your shoes few months ago. From my fresh experience i can tell you this:
AOW - you will get some practice and will try different type of dives. Basically these are simple dives in different environments. Course name is definitely misleading. After 5 additional dives you will still be fresh diver who has minimal skills to dive in nice and calm environment. From PADI perspective this "advanced diver course" sells better rather than "Level 2 course".
Nitrox - this is a good course as this certification gives you access to nitrox fills. However, basic nitrox is rather primitive and should be taught as a part of OW course. However, here PADI is able to generate additional revenue. Maybe in 90-ties nitrox was exotic and only technical divers were diving with nitrox, however, nowadays nitrox is very common (especially in liveabords).
Deep - skills that you will obtain are pretty primitive (e.g. to see how colors are changing in depth, how narcosis affects your body, how water crushes plastic bottle, to breath from reserve tank and simulate decompression stop). From another angle it is interesting to feel how your body reacts to deeper depth.
Wreck - this specialty gives you a small flavor of wreck diving, shows you how to do limited penetration to wreck. Quite interesting, however, this certificate will not make your real wreck diver
For example, i would think twice before entering any wreck despite the fact that i have this c-card
At the end of this month i am planning to take Rescue and few other courses as i like to learn something during my vacation. If everything goes successfully at the end of my vacation i will be PADI Master Scuba Diver. However, word "master" is very misleading. In my opinion, when you get MSD certification you become a reasonable novice diver who starts to understand in which areas you need to improve and focus. I would say that boyouncy, balance, trim and propulsion techniques are the most important skills in diving. If you master these skills and feel natural in that areas, you will can become good cave, wreck and etc. diver. If you fail in that areas it is no worth to go deeper in diving studies. You can become a real MASTER in diving maybe after 500 dives when you dive in different environments, in differnt conditions, experience and manage various situations. Even then there could be unexpected things which can put you of of control (e.g. unexpected sting of lionfish during a dive and etc.). Propulsion, trim, boyouncy are being taught in GUE Fundies, TDI Intro to tech and similar courses. In my opinion OW courses should be much longer and include these skills. However, then course cost would be maybe double or triple and much less people would take them.
Wish you good luck in your courses. Have fun during diving and with every dive try to learn, get more experience, monitor you breathing rate and see whether you are improving or not. For example, i felt biggest improvements in my diving during liveaboard when i did not have instructor but dive guide only, when me and my wife-buddy understood that we are responsible for our decisions and we have to rely on our skills during deep dives, dives with strong current. Also, we got a very good experience how to put loose tank back into place, how to deploy DSMB (it looks very easy when you see how your instructor is doing..... but when you do it yourself you see what mistakes you are making and learning from them).
