Rome II all the way!
“Tolerance, diversity, strength”

At release, vanilla:
Rome I was like incendiary pigs, burnt out fast and more often than not being near completely useless. But man was it awesome to see it all!
Rome II is like stampeding African war Elephants, unstoppable force prone to running amok,
but their glorious mayhem simply wont stop unless you quite literally pull the plug.
The former was no better than the latter at release and this has been repeatedly been pointed out by senior and veteran players, you may prefer burning pigs over scores of men sent flying but id take II as it simply seem so much more lasting and unwillingness of turning into ashes. The family tree missing is my main annoyance as well, but that falls short against the sheer simplicity and poor challenge of Rome I whoms political system was
barely any more explained than II's.
Even if we talk about current state as implied, Rome II still wins out in everything but the family tree...