If you are running mostly Skeletons (and thus soldiers) Id use Flank Attack over Power Strike.
When most of your troops are soldiers, Flank Attack is one of the most efficient Command spells in the game. It also rolls your Piercing Strikes and Power Strikes into one spell. +2 Pierce and +2 Melee for 3 mana is solid, and its setup can be triggered by any solider's attack, even ranged ones.
I had a skeleton build I tinkered with Flank Attacks, would do something like:
Archer shoots target, 4 dice
Cast Flank Attack on Skeletal Knight (or Mort)
Activate Knight (or mort)
-quick cast a second Flank Attack on the same Knight (or Mort)
-bonus points- Sacrifice a Plague Zombie or Skeleton Sentry on Sacrifical Altar to boost same Knight or Mort
Knight attacks for 11 dice and 6 Pierce, or 10 dice + Taint chance and 6 Pierce if Mort. (plus Rot if Plauge Zombie was sacrificed).
You can just as easily cast them on different skeletons.. thats just the flashy version.
Also, while Hawkeye is Living Only, you can simulate the effect by using Marked for Death instead. You will then get +1 for every attack on said target, which means if you have enough skeletons you'll actually generate more damage than a Hawkeye. Not only that, as a Dark Mage MfD is also cheaper spell point wise.