My only experience with the lower difficulty levels in DKS was in Farglow, where the summoned goblins did more damage at higher levels, and took less damage (at least as a percentage of their total health; I never checked the numbers on the actual damage done). On normal difficulty I did damage to them using unarmed attacks almost as fast as with my bow; on higher difficulty levels unarmed combat became less effective, and less viable with more than one opponent.
