One of the hallmark research items (and unique) for the Ottoman Empire is the European Doctrine, which is a prerequisite for the training of the "New Model" Nizam-I Cedit Infantry, Light Infantry, and Rifles. These new units bring the Ottoman Empire's infantry on par with their European counterparts. It is made available for research with the construction of a third-tier barracks - the Drill School. The tech "European Doctrine" itself takes quite a while to research - around twelve to thirteen turns with the best of colleges you may have with a few military-specialized scholars.
However, upon completing research of "European Doctrine," NO Nizam-I Cedit units are made available for training! The are only trainable from FIFTH tier barracks, the Army Vizierate. That means that if you research "European Doctrine" soon after successfully building your third-tier Drill School -
1. You have to research Socket Bayonet to build the next, Fourth Tier Barracks - probably around 6 to 8 turns;
2. You have to build the Fourth Tier Barracks, the "Military Academy" - takes 5 turns;
3. You have to research the "New Model Bayonet Drill" tech, prerequisite for the next technology - that takes around 6 to 8 turns;
4. You have to research the next tech after that, "Reorganized Procurement," prerequisite for the Fifth Tier Barracks - that takes around 6 to 8 turns;
5. You have to build the Fifth Tier Barracks, the "Army Vizierate" - takes 4 turns;
- in order to be able to recruit Nizam-I Cedit Infantry and Light Infantry. All in all, the actual technology, and getting the buildings - takes an additional 27 to 33 turns - or to put that in perspective, thirteen to seventeen years.
Does this system make any sense?
I know one counter-objection is simply "Don't research it until you have the buildings!" - but the huge distance between the technology for the unit and the building remains. I think the unit should have as its only prerequisite, the technology. If that means that the unit has to be made available in a Tier 3 Drill School instead of a Tier 5 Army Vizierate, then so be it. It doesn't make sense to give players a technology prematurely so as to confuse them like this.
The Sixth Tier Barracks, the "Army Staff College," and the tech "Machined Rifling" are required to recruit the third Nizam-I Cedit unit, the Nizam-I Cedit Rifles - but one can consider the rifle units a bit of a luxury and elite unit that is sensible to be made harder to access.
Off my main topic, I noticed that the "Machined Rifling" technology used to require "Machine Tools" from the Metalworking industry line of technologies - which requires a third tier Ironmaster's Forge and the enlightenment technology "Wealth of Nations," which requires a third tier Traditional University and three prerequisite economic-line enlightenment technologies. I looked at "Machined Rifling" again just now, and noticed that it doesn't require "Machine Tools" any longer on the mouse-over. Am I simply missing something, or has there been a change from the previous patches removing this requirement?
If the patches have been switching around our technology trees - I think I remember that Nizam-I Cedit Infantry and Light Infantry were available straight off from the THIRD tier Drill School (with research of "European Doctrine" of course) - the same proper tier where the technology is! If this was the case and is no longer now - WHY were the Nizam-I Cedits removed from the recruitment rosters???
Is this another case of CA royally screwing up again and adding more bugs???
Layman's version: Ottoman general receives word that the universities have compiled all the European military system and methods and he says, "Bravo! Now let's wait seventeen years until we can build this specific building before we can train these units using these methods and uniforms."
I know this is a confusing situation to explain and understand, but this is the clearest way I could write and illustrate it. Make sure to think a little bit after reading this OP.