Right now the Banshee's Veil counters any caster almost completely but there's no equivalent defense item to counter the big damage of auto-attacking heroes. Here's a suggestion:
+400 Health, +200 Mana. + 60 armor.
Passive: When attacked it applies a debuff on the attacker that halves attack speed for 5 seconds. 25 second cooldown.
The name needs tweaking obviously, but the general intention is to give the user a decent armor buff and let them possibly survive a couple seconds of being auto-attacked. The duration or amount reduced may be tweaked a bit but I think anything less won't really have any effect.