You must know that AI will constantly think about all the decisions it can´t make and not even see right ;-) so game will be a grinding halt by adding one little tag :-D
About the tag... As much as I like the possibility and sandboxy thing you can do... No... it´s too far fetched... Just as much as having norse religion revitalized in this period because some in scandinavia might still hold the faith in secret... Sry jews... You have to wait a bit to get your kingdom
First of all, I have no idea where you got this weird myth that "adding tags slows the game to a halt". If you cant link a developer saying that im pretty sure its totaly made up.
Secondly, if the game realy did check for every. single. posibility. ever. that would mean over 200 nations constantly checking to see if they exist for every one of the thousands of provinces in the game. And weather or not they should build a marketplace in them. So even by your false logic adding Israel wouldnt "slow the game to a grinding halt", it would slow the game to 0.0000008% slower.
Thirdly, Israel exists/existed atleast twice during history, though I would argue more. It certanly existed more than Scandinavia, Hindustan or The Kingdom of God.
And lastly, the question of weather the Jewish faith could ever survive in the real world and create Israel isnt the question here (although it did).
Paradox decided to make the Jewish faith playable. And in a game where you can conquer Europe with Ryukyu it certanly isnt impossible that a Jewish Horn of Africa nation could conquer up the Red Sea to the Levant.
... By the way, why did Paradox develop a costly feature just recently for Coptic nations to conquer Qara Qoyunlu or Alexandria? How does that combine with
As much as I like the possibility and sandboxy thing you can do... No... it´s too far fetched... Just as much as having norse religion revitalized in this period because some in scandinavia might still hold the faith in secret..."