Ok, so had another issue with factions. This time I was Arianne Martell. Prince Doran had just convinced Dany to marry my kid brother Quentyn, then died and I'd declared war on Tommen. Things are going good, even without Dany's dragons (stupid women-can't-lead rule

)
So of course, all of my vassals decide this is the perfect time to enact their "overthrow Arianne in favor of Quentyn" conspiracy. Never mind that I had taken the red keep, and was 90% percent on a war that would have made him a King. Nope, they prefer to lose the war in order to make him prince.
I held off ragequitting, instead surrendering, and reloading the save as new Prince Quentyn. Started up the "install Danerys" faction as soon as everyone became a vassal of King Stannis (who won the war when I forfeited). I had 300% faction power alone, so right away I issue the ultimatum. Bow or Burn, Stannis! Except right before I get my answer back, my power drops to like 5%. So we fight. Fortunately the Reach and Vale jump in on my side, everyone else is just sick of fighting and stays home. So the Mother of Dragons gets her throne. Though Quentyn is captured and executed days before victory, leaving Dorne to his infant son by Dany. <sigh>
Dany takes the Throne. At some unknown point thereafter, Aegon of Essos arrives and Dany marries him (I'm assuming an event?). She rules a fair while, rounding up stray counties and the Iron Islands with her "Kneel or I feed you to Drogon" CB.
In time, she passes away. So my now-grown Prince of Dorne is King. All hail Trystane I, titles titles titles, Brother of Dragons! Excpet all the dragon-related stuff goes to my half-brother.

I get that he's the (allegedly) purebred Targaryean, but couldn't I get the egg at least? For that matter, what happened to Viserion and Rhaegal? The non-dragon-rider King dies shortly after the birth of his only child by Robb Stark's daughter. Trouble, newborn king + dragon-riding Targaryean half brother...
In time I get deposed, not by my dragon-riding uberknight half brother (who is content to be master of arms of Bramsfort) but by the son of Robert Baratheon's bastard son Edric Storm, and his wife, who I believe was the last known Lannister. My computer wisely ctd'd then to avoid being hurled out the window.
In all seriousness, I think the faction system needs reviewing with regards to the mod. The AI seems to form factions and make demands when not appropriate (i.e, when your liege, a fellow dynasty member, is about to win a war and help their claimant) and not to form them when it would be appropriate (i.e, when you have a strong adult claimant and a liege who still has his umbillical cord).
Also, could we get 'special' dragon traits for Dany's trio? That way she could bequeath them to her heirs, or perhaps let a husband try to tame them. "The Dragon has Three Heads" after all...