(Dammit! I always forget about multiquote until it is too late! Sorry for the thread-padding!

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If you need a war to end for a specific reason then revoke the duke's title, it will typically end the war. You're not supposed to be an omnipotent ruler who can demand a completely placid realm for all eternity. Grow up.
I appreciate the challenge of the game (although your tone is a trifle forward...) - but it does seem to make a mockery of crown authority! If there was an option to discourage vassals from doing this via diplomacy (with repercussions like Tyranny or wider revolts) or to intervene on the part of "favourites" or to imprison people it might be better.
My problem with your revocation solution is that I want to keep my dukes! That is why I chose them!
One solution - albeit a bit late for me (and many of us!) is to NOT keep your dukes weak. If you give a duke 2-3 counties (depending on duchy size) they should be able to keep more than 50% of the levy total of their vassals which might prevent unstoppable faction-driven wars.
Absolute crown authority is usually always a bad idea to implement in my experiences as the negative opinions tend to get just a little too high to manage. It's fine if you have a really good ruler, but then as soon as you get some bad luck, die and play as someone poorer, everyone will revolt. It is perhaps a little misleading what the descriptions say, but I don't think that it's a bad thing and I think the game would be worse without vassals being able to plot to gain land under medium CA. Think about how it would be for you under absolute crown authority if you weren't allowed to try to gain land through plotting, your liege was loved by his vassals and you weren't strong enough to fight him...
Wel,. you'd need to be able to invite other rulers into your plot to overthrow him! I am really looking forward to being able to form "factions" between independent rulers in order to put friends on the thrones of minor countries. The option to be a disloyal vassal and invite your kings enemies into backing your attempt to bite off chunks of his kingdom should also be a possibility?
the best way to minimize fighting is to create kingdom titles and distribute them. that way you are less likely to have direct vassals at war
...
or I might be wrong :laugh:
anyway, it's not like your realm will be eternally having an internal war daily. even in my current ERE game with 600+ realm holdings, there will be the occasional moment wherein things are quiet empire-wide
that is when you're free to put the law to a vote
In the Kingdom of Aquitaine, with three ducal vassals, two of the three had claim-related factionally-driven wars at any given time...
The problem is we aren't even getting a day since many dukes/counts early game start wars they cannot finish as they cannot siege the province with the amount of troops they can raise. They just sit in war for as long as possible then white peace (if they are even forced to WP eventually...) while some other vassal is fighting.
When your fighting near constant wars against the caliphs not having a way to pass succession changes is overkill.
... and this is exactly what happened - they bash each other in the first battle and lack the troops to besiege either's demesne successfully waiting for the white-peace out option. And then another one pops up halfway through waiting for this to happen.
I guess I just need to make my dukes a bit more powerful so that a couple of counts can't take them down! (Gascogne was, but the clever plotters waiting until he was overseas on a Crusade..)