The point of factions is to add the forces fellow vassals of your liege lord to your own to make an ultimatum. If you're more powerful than your liege, you don't really need the whole system.
Like last time I tried to play the byzantines. I gave my children every kingdom. Very bad idea. I figure I should've kept Greece.
This game I'm doing better. Playing with a fantasy mod, playing as dragons, they're quite stupid, started Umayyad charlemagne-era, decided to give my kids and their kids Aquitaine, Brittany, Mauretania, Africa, Mali and Navarra so far, and I figure I'll always keep Andalusia to myself since that's the center of my empire now.
By "they're quite stupid" I mean I have a retinue of 10 dragons. The army size is 10. They can't besiege shit, but they can single-handedly take on the entire Karling army, as long as I only go for 10,000 at a time.
Oh, and my own levies have a total of 25 dragons. You can make a building that adds a dragon to the local levies per upgrade. Very very OP. Dragons get their own religion and the surrounding area are all heretics relative to that, which of course means I get to take duchies faster, though obviously I can't do the standard marry into claims thing, which is slightly annoying. Still, if you couldn't tell by the implication up there, I've taken over Aquitaine, Brittany and good chunks of Burgundy, Lombardy and some other would-be Karlingspace. The byzantine empire likes to declare war on me to take back Mallorca, which always turns out badly for them and gets me over 1,600 gold each time because the events in the game are hilariously broken.
Wait, okay, the mod has an equipment system. I currently have the top-tier warrior items. If I go to the warriors' guild and get a quest to defend a caravan, I'll almost definitely win, at which point I can show mercy and imprison them. Naturally, I promptly eat them, since I'm a dragon, and get 100 piety from that. I have the cruel trait somehow, probably from that, but it's a one-time thing and that's not too bad a trait anyway. I eat most of my prisoners. It's really quite convenient. Every time I eat them, I inherit their equipment, which I can then sell. If I do the second-tier warrior job, killing a troll, I get to kill the troll and sell off his weapon, a mithril hammer worth 662 gold for a total of 1062 gold gain from that quest. The dragonslaying job (don't think about it too hard) gets me a mere 800 gold and 400 prestige, for comparison.
My son sucks. I'm mostly immortal (sickness, wounding, maiming, infirmity, incapibility are all immediately healed and I can't die of old age) and so is he, so I've been hoping someone would off him. The only succession laws available in the empire are primogeniture and gavelkind, blech. All my kingdoms (I think I have 8?) are set to primogeniture right now.
Also, the damn karling won't die. He's the third Karling in the line so far (damn elves, also immortal), I think Karloman managed to get on top at first, at one point West Francia managed to detach from the big Karling empire, I quickly used the opportunity to get a pathway to Brittany so I could take that (since it was fractured into half-Karling, 2/6 independent counties, 1/6 England, which didn't matter at all), but now it's all one empire again and bleh, truces.
Basically, I'm trying to juggle carving out the ERE, Carolingia, Italy and Arabia. Arabia's got the world's second biggest army (Zakk, which is to say Abyssinia, has the biggest, but that's all goblins, which are utterly worthless, like unbelievably so, Asturias was also goblins and an army of 20000 of those can be taken down by 2000 normal soldiers, or, heck, probably a dragon or two), but I have dragons, so I figure I can take back Alexandria, which is actually rightfully mine since I usurped Africa. I'll probably eat the rest of the continent of Africa before trying to take Arabia, actually, that seems prudent. Taking the human (Byzantine) empire from both sides seems like it might be fun, since at least the humans have the common decency to die once in a while and make their truces disappear.