About the familly members of several barbarian factions, using the "teutonic system" :
I tested some of them in two ways :
1 : expansionism : I just make war to everybody and win the game. (that's the least funy part of the game I think). It works fine.
2 : protectionism : I just take one or two settlements and I resist as long as I can and intrigue and roleplay my game. That's how I like it. It is broken.
In situation 1, I just expand and conquer and get a lot of "familly members" and all works fine.
But in situation 2... I have a lot of familly member asking to join at the begining of the game. But when the time passes, I have less and less request, untill I have none. So my familly members just die one after the other, untill the unique situation where there is my faction leader and my faction heir.
Once one of those die, the game is over. Finish. So you lose the game because the game decided you didn't need familly members because you didn't expanded enough. (in some situations, a request of adoption is made and the game continue but it doesnt last long, next same situation and it is over)
It never occured to me with the classical familly tree. I played numerous of "protectionism" scenarii and it was fun. In fact, I had a lot more fun in those situations than in any other. (exemple : try to keep peace between Baktria and Seleucids, try to play a specific gallic tribe and not a union of tribes, etc)
So here it is... If you play the game like any dumb vanilla total war it is ok, but if you try a situation where you may have a lot of fun, it is impossible.