Playing 6.1

Two field battles I've played have shown the opposing army standing, holding their lines while taking heavy ballista fire from my army. No archers at work on either side, just my cav and inf standing tall and my ballista crew firing away. The enemy just take the barrage before reaching critical numbers, and then retreat, only to be run down by my cav.

I'm playing on the hardest difficulty and enjoy the dominating victory but I favor as much realism as possible. Any others experience this?