Mmm, not sure how that can explain the unit preventing a counter-attack, really! I can see it getting reflected, or dealing less damage, but still! Methinks that's a feature that could be used for something like Stab- where the assassin is so fast, no one has quick enough reflexes to respond.
Otherwise- I don't really see an enemy with just a shield becoming an offensive unit and dealing much damage!
What I would actually like to see, is some unit which can use Whirlwind- in fact, why not a Helenite melee units all know how to perform this attack, since Helena taught the rest of them how to use it? Powerful, impressive, deadly.
This unit will definitely be a challenge, with ability to break formations and preventing the player from attacking the unit an all sides, unless they're going for a sure kill.
Helenite Swordsman
Health: 40
Speed: 3
Attacks: Melee (Range: 1; Damage: 12), Whirlwind (Range: Omnidirectional; Damage: 10)
Resistance: none
Immunity: none
Thoughts, folks?