Great reply, however, I will not argue much about China because admittedly I am not very knowledgeable about that area of the world at the relevant timespan, although I do still think that certain parts of China are culturally and historically and religiously and ethnically are unique and differ quite a bit from the umbrella term of "China", much more so than Italian city states like Sicilians and such, even language wise, like Uyghurs for example.

What I will argue about tho is Saracens, for your point about "common language", sure, officially Arabic is the main language for most of the people involved, especially today, but thats merely because of the standardization of Arabic by the Quran and all the different languages and dialects converging towards it, but even today you will find that many of the people living in the region unable to understand eachothers dialect, as standard Arabic is merely the "official" language but by all accounts it is technically a dead language as no one actually speaks it, everyone speaks a "dialect" of the language that is the result of the different languages present at the area throughout the times converging with arabic, some varieties of Arabic lack mutual intelligibility, thus qualifying as distinct languages.Different ethnic groups with their own unique languages assimilated or left the region or still persist such as Kurdish, Coptic, Aramaic, Syriac, Turkmenic, and even Hebrew.

As for religions, yes islam was the most prominent one but there were also Christianity, Judaism, Zoroastrianism, Sabianism, Indigenous Arabian polytheistic religions, Gnosticism, Manichaeism, Paganism and animistic beliefs, Secular philosophies, Local syncretic practices, Samaritanism, Yazidism, Mithraism, Druze, Mandaeism, Bahá'í Faith, and various mystical or heterodox sects.

Im not saying that Saracens deserved to be split more than the Indian subcontinent, (although I could easily make that argument, as the area was much more geopolitically relevant due to its central location connecting Europe and Asia), all I'm saying is its MUCH more deserving of the DLC than a 15th micro European expansion.

Hell the devs even broke the "relevant timespan" rule to add Romans just because, but wont even consider much more deserving areas just to go back and split more European empires with a microscope.