I noticed this with dismay too.
The use of children to bind vassals to you with NAPs wasn't by any means an exploit, nor was it overpowered. It added a very strategic layer to the game where really your children were already missiles. Missiles to be used carefully and with planning. To be used externally for claims and expansion or alliances, and now internally to maintain realm peace.
These missiles were not infinite, not even with seduction focus especially not now.
From a vassal standpoint even if there is no overt risk of title revocation(like you're a Zoroastrian under the Caliph) locking yourself out of factions for a bit can still be worth it. The opinion with your liege, the fact that you're marrying into the royal line. Protection from what could be one of your greatest threats, and a claim on his throne, the prestige from the marriage aside?
The notion that vassals would prefer a better NAP then a NAP with a liege in certain situations is reasonable.
The notion that vassals would so uniformly and arbitrarily grossly undervalue a liege's NAP isn't.
But I don't think this is about what the AI should and shouldn't look for.
This is about them introducing added challenges to the game in Conclave, and with those challenges added tools to deal with them.
Only to see us using those tools, and proceeding to take them away.
There is no reason why so many vassals would so generally say no to a betrothal / marriage / NAP with their liege in this time period.
Do the developers of this game seriously think that the use of inter realm NAPs between Conclave and Reaper was imbalanced towards the player? That vassals being open to liege NAPs made it too easy to maintain inter realm peace?
Yes this is an assumption on my part that this is why it was introduced. And if I'm wrong you have my apologies, but if I'm right.
This game needs a challenge and it is a challenge. But if you are going to stand there and tell me that I should be able to manage this realm and its vassals with the tools given to me, with half of them saying no to NAPs I am going to cry bull****.
Yea what tools are those?
Honorary titles for 5 whole opinion and everyone only gets one? (Because of course that was medieval law that everyone only got one honorary title.)
Gifts, which have admittedly been buffed?
Council seats for everyone important?
Make sure everyone is de-jure where they should be?
Land grants and feeding? Land grants can hardly be counted among the player's permanent tools for vassal appeasement when land isn't always had to be given.
Plop the chancellor down for some relations, the spymaster down for some scheming? (Councilor actions have been more rapid, we still aren't sure if this is intended or bugged)
And after that what is there, oh right the children, the most precious resources to be had in the world. The resource on which all of your plans and livelihood depend upon.
Send the younger ones off to be educated by the powerful duke?
Risk your future and send the heir himself off?
There are of course other strategies, I always try and educate vassal children under me, or the future me for the mentor bonus.
But the reality is that all of these tools combined aren't enough.
NAPs did not need to be nerfed and the player did not need to be leashed. Especially not using the ancient opaque +++++ ------- system that the player base hates and is eternally perplexed by.
With half the realm refusing NAPs the player does not have enough tools to actually manage the realm and play the game.