The game could use a party or just one hero. If there was a party, you could select the hero that best suits the encounter. It may not always be the one with the best scores, especially if they've already taken a lot of strikes. So you have a list of options, in the form of party members, and you risk the one that you use. Some heros may have special abilities that affect other heros as well, so you may be able to combine their efforts.
Maybe there's a way for party-vs-party combat. Got any ideas?