This is my last post on this topic.
I realize your attachments to the Ottomans Txurce. I love playing that civ because of their overpowered trait but have a moral aversion because of the atrocities and repression of so many other cultures, much like I won't play the Romans and a few of the others.
I'm rather well-read on history; it was my college major. Their imperial palace in Istanbul was an impressive place full of imported scientists and military specialists. The rest of the empire was rather depraved and presented the worst examples of inhumanity and despotism in the near-modern Western world.
Proposals:
1) Give the ottoman trait to other civs and give the Ottoman imperial palace a special boost of culture, science and productivity. Give them cheap slave armies and pirate ship conversions representing the Barbary states.
2) A temporary quick fix would be to let the Ottomans keep their special 4 point specialist bonus but reduce the Great person bonus to 1. Imported scientists and engineers would rarely stay beyond their contract. A better temporary fix would be to give them the chinese trait of Great General generation and a special building representing their dominance of the spice trade.
3) Consider boosts to other civs involving creative management. You mention the Germans. There were German military advisors in the Sultan's court all the way back to sacking of Constantinople. The Germans armies was various and may have included excellent, but costly mercenary halberdman, just as the Swiss. The German states were at the forefront of fortifications and their courts generated a stream of Great People: from Leibniz through Kant, Hegel, Schopenhauer, Marx, Nietzsche, Heidegger and Wittgenstein to contemporary philosophers. We cannot forget to remember Bach, Schubert, Handel, Mozart, etc. The Germans states could never unite until they were overrun by Napoleon, but they had a common language and heritage. Nazism was an exception in their history.
4) I'm not a bit German and believe other civs should be able to showcase their unique heritage. The Americans and English seemed to share a special Merchant trait that is not showcased. Spain's civ is bizarre and unplayable. Spanish and Portuguese speaking players form large portion of the Civ 5 population and they would love any enhancements.