Why would you take atk+ when you have so many better options to pick from? For example def debuff from the same Gawain.
I did auto battle both experts Crom with only Nike as healer... But fire is weak to water so... I guess it depends? I would say at least one strong healer is required for party, 2 if you want to be really safe. I really hope that I will get Aphrodite someday....