Orcs and Oni aren't close to broken. Regular Goblin Archers hold off attacks until you can get -1 cost on Shortstacks. Once you can get 5 in a side, you're golden. Get priests in the stockades and they heal even female monsters. You can drop Shortstack to -2, at which point you're putting 10 shortstacks in a group. It's insane. Archery with cleave is so dumb.
Orcs and Oni on the other hand have to walk forward and keep getting hit and knocked back. Meaning they must lose health. In addition they have a slow melee attack they only start when in range of the enemy, instead of before. Meaning they often get hit before they hit people.
Meanwhile the rank and file goblin with a bow, with no enhancements at all, can keep firing when being fired upon because his attack is quick. The more attacks you put out, the more the enemy flinches, the less attacks they do, the less damage you take. The combat does need a serious rework for both the attackers and defenders.