Hi there!
After looking at the preview, I noticed several things that does'nt seem to me accurate enough. The first among them concerns the Great Seljuks Empire. It is portrayed as the most powerful facion in the game, but the Seljuk Empire was no unified domain like the Roman or the Sassanid Empires. It was nothing more than the domain of a family (the Seljuk family) allied with many warlords of the Near and Middle East.
The story of Basil Akritas, a Digenes (half-blood) lord, son of a Muslim Amir and a Byzantine noblewoman, lord of the eastern Empire's frontiers and also of no man's land between the Roman and the Arabian Empires, is a proof of it. He was like El Cid in Spain. Basil and many other frontier lords from the Roman Empire, from Armenia, from Georgia or from the Caliphate moved between loyalties, seving their own interests. None of their central governments had the strength to force this lords to be loyal.
That's just an example of how the Seljuk Empire was in fact fragile and susceptible of desintegration if the Sultan was not an iron ruler. Perhaps Malik Shah was a strong Sultan, but his dead is usually settled as the year of the desintegration of the Seljuk Empire, which is not correct. The Seljuk Empire, as most of the Western and Eastern kingoms in High Middle Ages Europe, was in fact the family and thier clan friends and allies. It was not a centralized Empire such as the Roman. It had little intern cohesion, and even lesser centralization or complete domain over the provinces and frontier regions. Mosul, Aleppo, Damascus, Khorasan, Basrah, Oman and other regions acted almost as independent rulers. That's why at the death of Malik Shah, the struggle for power between his four sons(4 or 5? I cannot recall well) led the empire to desintegration.
So, I think that portraying the Seljuks as a unified great and poweful Empire is, from my point of view, a mistake.
And other minor issues:
I noticed that, in the map, Castille controls Valencia. That's another mistake, even if you say that Rodrigo Díaz de Vivar, El Cid, was a vassal of Castille. That's true, but El Cid always did what he wanted. What is more, one of the daughters of Rodrigo, called María, married with Ramon Berenguer III the Great, Count of Barcelona. One of the excuses given by king Jaume I of Aragon was that Valencia was him by inheritance, as the major surviving descendant of El Cid married his grand-grandfather.
Besides, making Castille control Valencia would close Aragon's access to reconquer Muslim territories. Too early for that, I think.
Just one last thing, related with Aragon again. In order to represent the naval and commercial power the Crown of Aragon had since the XIIth Century (one of the reasons for the conquest of Mallorca was their importance as commercial enclave and the fact that the Muslim lord of Mayurqa turned the Balearic islands into a pirates nest) I suggest the institution of the Consolat de Mar, meaning this Consulate of Sea. This was a commercial tribunal and also an institution to rule and regule Catalan trade over the Mediterranean.
The Consulate had many "colonies" called Alfòndecs, in important trade cities of the Mediterranean, such as Genoa, Venice, Tunis, Marseille, Palermo, Alexandria and Constantinople, among others. Those colonies, very similar to what Genoa and Venice had, were not just trade centers and hostels for Catalan merchants, they were also embassies to other countries and spy bases. I think that this can lead to interesting characteristics for Aragon.
As a curious tip, during the siege of Constantinople in 1453, a Catalan company of soldiers defended the sea walls of Boukoleon and the ruins of the Great Palace, lead by the Sea Consul Pere Julià. As far as I know, they all died.
That's all.
Take care!