[Twan]

I agree about artefacts (or expensive level 6 items for some spells). As items are the only way to use something before the defender cast, new items with defensive spells would solve the attack/defense balance problem.

The most powerful defensive buffs (army of lead, fog warriors) don't have to be available on items, but mid-power ones (ie : mass protection, antimagic, protection or resists spells with limited AE like marble warriors, legions of steel, and ward spells) should, and would be sufficient to avoid sure victories.