Rome, Parthia and Kushan, all were eventually brought down by civil wars and rebellions. Because all these major empires were incredibly fragile from the inside even though they were unbeatable from the outside. Because otherwise sitting there not expanding for a century is going to be incredibly boring. Everything from CK2-level character interaction and features, to more detail like dynastic estates and to loads of positions and posts for people to cling to and such, to squabbling and backstabbing for power.or even the ability to play as a character in your empire.

I am not asking for a Caesar 3 of course, but something on provincial level. Indians and Persians established huge universities in Takshashila and Gondeshapur, respectively. Famous people had began their careers running a city. Roman emperors spent years founding cities for one reason or another, and then building it up to the mark.

City building and management elements, related to the above.

But how will this game even implement such thing, when it has so few things to build and forget? Why? Because that's what occupied the time of most emperors. Each of them have to be maintained, staffed and such. Yes, loads and loads of buildings, each of which require careful consideration into building about location, resource, price and so on.

Some emperors are known not for their military or political achievements, but fixing or ruining currency. Because all three civilizations (Graeco-Rome, Persia, India) had their economies collapse the moment they tampered too much with coinage.

A system of coinage and ways to influence it.

So it all comes down to detailed internal empire management.and that is something Paradox games (especially with EU-like features) don't have. They fight a few wars, occassionally gain vast swathes territory.but otherwise they put a bunch of client kings and leave, and borders don't change much. These empires are too large and in a position where they simply can't attack each other without having their empire collapse, or the player getting bored due to lack of mechanisms. The entire map consists of three giant empires - Principate Rome ruling the west, Parthians running a large empire in the middle, and the giant Kushan-Satvahan empires ruling India in unison (alongside entire central Asia). There are certain things to be taken into account for that timeframe.

Mount and blade warband imperial age