The longer I play Bannerlord and read these forums, the more convinced I become that defections need to be abolished.
Just get rid of the idea.
In Warband, the best you can say about defections is that they made the game a bit messy; in Bannerlord, it just ballses up the whole game.
Now, I'm aware that players need a way of recruiting clans into their own faction after they start one. I think it'd be better all round if clans that leave or are expelled from their starting faction should become independents, and a functioning role in the Gameworld found for them while they are independent.
It's just weird that at the start of the game's scenario, each faction's clans are neatly organised according to their culture, and then within a few years they're all mixed up. In terms of lore, continuity and immersion it just doesn't make any sense, and in terms of gameplay it creates a whole raft of balancing problems.