Use the magicians for ranged attacks, use magics like grease, acid pool, make combos like greasing the terrain and then fire it to add fire damage, when in closed spaces check for oil barrels to use at your advantage, when possible try to use narrow passages to force mobs into a bottleneck, use bless, rally, use jump and rush to put some distance from melee attackers.
Also for enemies you know you are going to attack choose carefully from where hit them, and be careful mobs from similar factions will gang together so before going against an npc control how many of its peers are around and then decide if you need a camp rest or to refill your supplies.
