Right now, if your party has three chars, your inactive chars have their "Add to Party" button greyed out. Since that function isn't available, why not change the button to something like "Remove Entire Party and Add This Char"? Right now it's rather a pain to swap entire parties because you have to have one char in the party at all times, so you have to Remove, Remove, Add, Remove, Add, Add.
Agreed. Or change it so that it swaps the inactive character with the currently selected character in your active party. Incidentally a drop-down list of available characters who are "on the bench" would be nice as I keep having to click through all the tabs to find the one I want.