Vs Armor March in Arena

I feel like as long as you don't rush and check each of the opponent's units' skills, it's actually easier. From my experience, the armored units will usually disperse depending on the map, so not only will they lose their armor buffs from not being next to each other, they likely won't be able to use Armor March anymore. From there, you can usually just attack them one by one to eventually defeat the whole team.