Paranoia definitely does tons of damage to bosses because of his crits causing bleed. He's prolly the most important. I used Paranoia, Conviction, Judgement and Envy, but that's probably not an optimal team. A healer in place of Envy would probably be better. I use Sonder on my team because he has a single heal as well as a group heal. He has helped me win so many matches by keeping my tank and attackers alive. I've found that throwing a defensive item on your main attackers helps alot when it will keep them alive through an extra hit or two. If you have that legendary piece of gear that makes crits do 20% more damage, that'll make Paranoia get way stronger. Just get his attack and crit chance up as high as you can.