well, speaking directly in game terms, all you need to build dreadnghouts is shipyard (on map facility) + some extra naval build capacity. Turkey do have shipyard at izmail, but lack that extra nb, while constaninople naval base nicely provide needed exra naval capacity it simply lack needed shipyard there.
just look at gerany and stetin - you can build dreads there (because port here is biger than lvl 1, unlike as in izmail case), if you dont build/repair anything else there. But were here dreads build historicaly, or only at wilhemshafen (and mayby kiel).
And yes, i fully agree with you that if otomans wanted in reality to build dreads, they will need to put extra effort for it, but why not provide player with ALTERNATIVE ? just to give player some freedom in way how he want to play this game.
and concerning technology needed to build dreads, well regarding armor plates, it is more of technology proces than machinery related, so relative easy to solve, building of big enoug slips is just matter of manpower and resources invested in existing ones, so most easily to solve, building of big enoug guns will be biggest problem, if they lacked big enough machinery. for propuslion, well, if you can build it for heavy cruiser, you can build it for dread too, they were not much bigger, just increased in number (say 6 turbines instead of 4).
After all, players do have option to chose from 4 warplans , insted of only historical start up. why give players freedom there but deny them elsewhere ?
and when speaking about alterntives, this game have potencial for them, but fail to deliver them. just look at bulgaria, player only have option reconize bulgarian wargoals as cp, and thats all, it totaly lack any option for entete to recognize bulgarian wargolas too (but with way smaller effect since they shold offer bulgaria waay less land than cp).
one of resons why entete failed to help serbia in time, was because they hoped they can bring bulgaria to war on side of entete (which was doomed to fail because cp simply can give more), and in end hey decide to land expedition forces at salonika, not only to late but in small effect.
Imagine if they decided to land expedition forces at albania, or at worst negtiate arms and supply transport over albania to serbia, shortly after war started, not after 14 months delay and on salonika. suppling expedition troops at albania will be way easier for entete than on greek salonika.
but in game albania is "insvisible" state, you cant event make diplomacy with him.
and same historical alternative is not here for romania, only entete can recognize roms wargoals, not cp, which did have nice bargain token too (they should offer way less austrian territory than entete, but cp should offer as very nice bonus bessarabia (moldova) to romania.
again, this option is lacking.
and if you think more about it, you will find more and more alternatives/options lacking.