+1 to both suggestions - possibility to manage all companions in camp and party selection screen when you leave it (this option should be able to get toggled off via menu option though for people, who want to keep the same party and not choose similar people every time they leave camp). Larian have also already created such a selection screen for one of their Panels from Hell (Mage Tower one, where people determined the party composition for it), so it is not a problem for them to create a similar one for game itself if they want to.
It would make sense to have the former party preselected, so you only need to make changes if you desire to do so.
