So I learned about how annoying adventurers are.
I was playing as Mecca in the Shattered World mod and had created a pretty powerful Caliphate covering Arabia and Egypt. I was informed that my random idiot uncle was gathering forces to take over, but I was comically rich so I simply assassinated him. A few years later, when I had just finished a war and was out of money, my random idiot cousin (son of aforementioned idiot uncle) decided to do the same, but this time I couldn't assassinate him. "Oh well," I thought to myself, "I have about 20k levies and the next biggest country has maybe 6k, so I'll just beat him in battle!"
When he attacked, however, he somehow had 30k troops. Apparently he managed to amass an army significantly larger than that of the Caliphate, the largest nation in the world by a longshot, despite:
-The Caliph being beloved by all of his vassals and people
-The Caliph having pretty much only positive traits like "Just" and "Kind", being known as "Uways the Holy"
-The cousin being a random idiot with shite stats, next to no gold and a very weak claim on the throne
I managed to win by destroying the invading forces as they stupidly attacked my forces in Sanaa (mountain province) 10k stack by 10k stack rather than attacking full force or playing cautious. It's still a very stupid mechanic the way it is now.
Also, I thought decadence was fixed and at first it seemed like it was, but now that my family has several hundred members spread throughout the Caliphate I'm finding out how broken it is. In particular, I have several decadent cousins generating massive amounts of decadence because they aren't in my court, get talked to by their lieges (other idiot cousins) who fail to convince them, and then inherit a bunch of land. I can't talk to them because they have already been talked to, I can't arrest them without incurring a tyranny penalty because I didn't get the justification from having talked to them, and I have a hard time assassinating them because they aren't in my court + they often have good intrigue because almost the entire first two generations of the family consists of Geniuses. I arrested two of the biggest offenders and simply accepted the incurred tyranny penalty, but then discovered that this precludes me from using Ramadan to reduce my decadence because it forces me to release my decadent relatives. It's generally very dumb.