Upgrade or alternative upgrade?

Here's how I would approach unit selection, focusing on countering the enemy and complementing my own build: 1. Against ranged units and spellcasters, armored units are often a good choice. 2. Against dark magic users, Paladins are effective, or you can use Dwarf Shieldbearers and deploy Imps. Armored units can also be used if you're not worried about Zealots taking out some of your units with their powerful attack. Against dark magic, Archangels are also a good option – it should be clear why. 3. Against attacking units, I would take crossbowmen, as they might survive long enough to get off another shot. You can also take Seraphs if you think someone will die quickly under high damage. However, Archangels are always in demand. 4. Against heavily armored units, take attacking units: Zealots, Imps, archers, and militia.