Honestly I would prefer it to be the estimated solo-run trait like lonewolf, if you take it, you can't take NPCs and you can take it from start.
Yes, me too. Or if you take it the bonus is dependent on the number on NPC you have. Perhaps if you pick one up the bonus drops, you dismiss them it goes up again. At the moment it is a ridiculous boost if only one character requires it. Like an OP leadership.
I'm testing giving it to all 4 but had to start again from the beginning... My guess is giving it to the other 3 will do nothing extra but we will see.