All of this is interesting, but it's been years since I made this mod and I have basically lost all knowledge about modding this game. It's officially abandoned.

About the taifas what could be done about them? They are 300 years in advance and one like emirate of granada, almost 500 years.
The taifa of Zaragoza could be renamed "Banu Qasi" (Sons of Cassius) and have some European looking units, as they were basically Basques that became muslims.

Maybe making separatist factions like Aragon, Galicia, Catalan Counties replacing their ismalic counterparts?

So true, even the early Greek rebellions in the modern era in the 1800s called themselves "Rhomaion"

All the remaining Hellenic speaking regions of the ottoman empire called itself "Roman" so much the identity remained strong, even in modern turkish these greeks born in turkey are called "Rums"

That's Not Right. The Byzantine Empire referred to themselves always as Romans and Pater as Greeks. Byzantine is a term which was Established by modern historians. (That's why Justinian wanted to reconquer Rome)

Furthermore the both "Romes" were actually still considered as ONE Empire, but with divided governments, at the start of the Attila Campaign.

Eastern Roman empire was called the Eastern Roman empire until the Western Roman empire collapsed, then they called themselves the "Byzantine empire" because there technically they coulden't call themselves the Roman empire any longer. Also, they got split, so they can't both be called the Roman empire.

I'm proud of you my son. ;D