Rally With Ninjas Suggestion

The experiment feature happening in the story mode "Enemy of the State" where the team you are fighting increases the difficulty after each match has inspired this idea.

A rally fight (maybe in the deadpool event, where you would get one attempt a day) would allow you to fight a wave of ninjas. After the first wave, the second wave would come in a couple of levels stronger. It would have an infinite (okay, well maybe 50-round max) amount of waves that you would have to fight with just your original team. The point would to complete as many waves as possible until every person on your team was dead.

At the end of your game, you would get a reward for each wave completed. It would be like a mini-tournament you could complete each day.