problem with sacrifice was that you could have an infinite source of units of everything. One of the balancing factors in the game is the (low) availability of certain troops, but Sacrifice killed that factor.
I suppose I never experienced it without it, but I did find the units generally pretty well balanced. The units I kept I kept more because they finished the combat quickly and more enjoyably than because they were ultimately more powerful. My main overpowered unit was the royal snakes and most of those I bought.