Simply as the question says really, what is the reason that in past Total War games there have been hardcoded limits such as 199 regions + sea, or 500 units?

How easy would it have been for CA to decide to increase the unit limit in M2:TW to say, 1000? A simple text variable?

It just seems that seeing the fuss over the limits in the previous games for modders, wouldn't CA remove the region/unit + other caps altogether for Empire: Total War? Or have they?

I heard that there is no region limit in Empire, which is good now because it can mean an extremely fun campaign map with a lot more to do, but what about the unit sizes and number of them?

I was thinking maybe the reason for the limits in past Total War games and in Empire is because it causes instability?

Anyway please discuss (sorry for so many questions here)