Jay suggested that area of effect attacks (Dark Forest Witch, Storm Friar, Marsh Warden, Rune Dancer) would be better if they affected individuals, rather than units. So each individual in an army would have a small chance of death.
The result would be that it wouldn’t matter how many separate armies the zombies were in, and you’d do more damage against larger armies, no matter their configuration. Also, when taking friendly fire from the Storm Friar or Marsh Warden, your heroes wouldn’t automatically be killed, they’d be much more resistant than individual soldiers.
What do you think?