I've actually felt very little desire to swap out characters so far. The way the game works now even characters at camp will approve/disapprove of your choices. I'm not even entirely sure if you need to take characters along on their personal quests - though I do generally do that.
I don't want to spoil anything. But depending on your party, your type of character and story choices. There are companions that will attack you and when they are dead, they are dead!
