Way, way too easy. If you have max mana regen and the best rain of arrows, you don't have to do anything but cast spells to win every battle. It's not really worth your time.
having a couple of gravity gunners w/ leech, impact, and damage mods. Along with a sheriff w/ auto shotgun makes the best team in my opinion. Usually go for the rouge as the main for all the extra money. Make sure the two gravity gunners are different classes to get different party skills.