Last week I did some simple tests via custom battles against the AI, sending 100 archers vs 100 infantry, with various factions. I did not intrervene, just wanted to see the AI in action. These battles were very onesided, as one can imagine, the infantry usually ran away before reaching the line of archers.
The one noteable exception was the Khuzaits however. They caused heavy casaulties with javis to the archers from 40-60 m, and in one occasion (against Sturgian archers), they even won the battle. Not tested javis vs regular infantry, but I am sure the results will be devastating. I believe a full javi army will be op in campaign as well.
There are a lot of consideration of course, like the AI not using shield wall etc, but I find it somewhat immersion breaking for me to have such high damage output from ranged weapon - considering the game's medieval settings. What I would like to see is melee oriented battles, where the ranged troops are strong, but mostly supporting units only.