Give your melee fighters more mobility skills. Phoenix Dive, Battering Ram, Tactical Retreat, Blitz Attack, Backlash,... Battle Stomp also clears surfaces & clouds. Have a mage use teleport or other transportation skills. Or just make sure to boost your magical defences/resistances(with spells/potions/food/...). Preparing the battlefield before the battle also avoids some of this. Mobility skills are insanely handy.
What difficulty are you playing on btw?
