You lack a melee opener - Frost Nova/Fear on sight to prevent the Rogue from ever getting a clean Cheap Shot off.
Mirror-ish caster matchup - Mana Burn the enemy healer aggressively since both sides can out-DoT each other otherwise.
Both sides have the same burst-plus-DoT toolkit - whoever lands Fear/Polymorph on the enemy Priest first usually gets the cleaner window.
This favors you - your burst closes fights faster than their pure attrition plan; press early rather than settling into a long grind.