I'm actually sad that Crusader Kings 3 doesn't include China as well, maybe an update will. Imagine playing with the Mongols from the start.
Why would that make the game worse beside sacrifcing a deeper, more immersive, and richer experience? which I don't think is the case. You can have both.
The real question is how. Say you are the team developer of Crusader Kings 4, what game mechanics would you create that would make CK4 a deeper, more immersive, and richer experience? because I think the devs have done a pretty good job with CK2 and CK3. The last DLC of CK2 especially was just amazing. I find some EU4 DLCs kind of meh, some HOI4 updates I actually hate, but in CK2 and CK3 the updates were always amazing. The team is on the right path if you ask me.
The crusades are the "main event" of the game, Crusades and Jihads, which are basically an all-out war. But CK2 & CK3 aren't games about Crusades in spite of its name. They are games about feudalism.
The core idea of the game is that if you play with the Byzantine Empire, you don't play with the Byzantine Empire, you play with the Byzantine Emperor, as the Byzantine Emperor, the person who owns the title "Emperor of the Byzantines". And your goal is to:
- Not run out of money
- Make sure not all lords under you hate you or at least not a majority
- And/or have a strong enough army so that you can stand toe to toe with them
- Win wars and conquer lands if you want, conquer lands to other more sneaky means like alliances or assassinations
- Make sure someone doesn't assassiante you.
- Make sure some other kingdom around you isn't stronger because then he'll try to take your land.
- MAKE SURE YOUR KID DOESN'T GROW UP TO BECOME AN IDIOT (I wish a lot of real life rulers kept this in mind, especially the great ones like Catherine the Great, it's almost like if you take the "great ruler" perk you have to give up the "great parent" perk, like HOI4 mutually exclusive focuses)
- Make sure you deal with the plague or other calamities that may arise.
- Make sure you deal with random events well.
- Play with religion, prestige, personal focuses, holy orders, adventures, mysterious people, etc. (I dislike the perk system because it's kind of cheap, but meh)
- Make sure you develop your castles and your regions under your rule so you will have better army.
- Make sure you get to have the best territories in the kingdom as you can.
- Building new towns and churches in the best territories you control.
- Picking a good council but make sure you don't get others especially powerful lords to hate you in the process, so you have to compromsie power/efficiency.
- Take care of the laws inside your kingdom especially taxes, inherance, crown authority, etc.
- Make sure the other members of your family don't want to take your titles at the same time make sure your family doesn't die.
The idea of CK2 and CK3 is that it's difficult to keep all these under control. You can't have big army and big chests at the same time. You can't have big taxes for the lords and laws that say that the lords contribute a lot with their army in your wars & have the lords love you at the same time. You have to strike a balance. Between them not hating you and you getting something out of them. And because it's CK2/CK3, bad things will always happen, it's a random chance away from bad stuff happening like your lord dying randomly on the battlefield or of plague. Stuff like that happened in medieval Europe. Stuff that ruin all your plans. You can't have inheretance laws that say only the first born gets everything and not have your other children get upset.
Admittely, CK2 was more difficult which is why I like it more in this regard, but CK3 kept the same spirit of careful management alive, and also giving a clear example why feudalism was doomed from the start, it's a guarantee of in-fighting with flexible laws and everyone vying for power.
That's the whole idea of CK2 and CK3. That's what it's all about. The crusades are just a big event in all of that, but not the main thing.