A duo of Lone Wolves is stronger than a full party : you scale faster/harder, you will gear way easier (you don't have to buy armors for 4 people, only 2), more AP during combats so not only your character hits like a truck BUT you can do more actions and just 1 turn kill a priority target.
With a 4 party team, you will be always weaker, because of how turns work in this game (you > enemy > 2nd member > enemy etc etc, ALWAYS, initiative means shit). The only plus for a 4 team is more civil abilities and more quest lines.