Depends how the Shield works. If I've been talking about it as a counter to Vikings this entire time, and its traditional use wasn't, then it's common sense that the ability ought to be modified so that it can be used that way. Have it act as a temporary Hardened Shield, reducing incoming damage to no more than 6 per hit. Have it act as a 3 second invulnerability. Have it cut incoming damage directly in half. Any of these would have a stronger effect on Vikings than other units.
Depends how the Shield works. If I've been talking about it as a counter to Vikings this entire time, and its traditional use wasn't, then it's common sense that the ability ought to be modified so that it can be used that way. Have it act as a temporary Hardened Shield, reducing incoming damage to no more than 6 per hit. Have it act as a 3 second invulnerability. Have it cut incoming damage directly in half. Any of these would have a stronger effect on Vikings than other units.