I haven’t played CK but clearly it is a very different game to EU and a very different time period so you cannot simply combine the two.
That said I find two aspects of EU to be both bad game play and ahistorical.
First of all the fact you are simply “presented” with an heir and their random stats determine virtually everything important in the game from technological progress to development to expansion. I have just been reading two biographies in 18th century Russia and the Tsars, actually had the right to appoint their own successors in that time period. Incompetents, or 1/0/1 in EU terms, might be liable to imprisonment at best, beating to death at worst. Before that time heirs needed to be approved by a council and the eldest brother could be set aside for the younger if the elder were impaired in anyway.
I’m sure many other countries would have had something similar so would not necessarily need to accept their 0/0/0 in the whole of the game period.
Secondly the process of getting and training a heir was something a number of rulers took a great deal of care over, which again makes a random number generator determined at birth unrealistic.