I feel like I have no say in who joins my crew or not. I was hoping as being a Captain, I could reject or accept people into my crew, if at least let us reject or accept people outside of the story. Like we don't have a say in Bonnie Anne or Ratbeard, but we could reject the monkey crossbowman or watermole slingshot.
I would also like for characters like the monkey crossbowman and any other side-quest type companions would have more to them then "Oh you collected 5 fish, I'm going to join your crew!". I would like something more to it then that, like "My town was burnt to the ground, family help captive and now they are coming for me, please help me pirate!". Then when you help said companion, he/she feels obligated to join you and even then you would still have the option to accept or reject said companion, but not like a blunt "No". If you pick no, you explain how your family needs him/her more then your crew does, but you will always be available to help. If you pick Yes, that could be pretty blunt, maybe a "Welcome to my crew matey".