I didn't encounter varying game speed, both battles seemed about the same to me.
I tested Chalons by staying closely deployed and relatively static, the AI performed a coordinated attack. It was nice to see them regroup before advancing on my remaining units.
By using the Chalons map it is relatively easy to rout the enemy because of the tactical options. If you don't use the map to your advantage then things are different.
I don't like Alan mercenary HA having better stats than Hun HA. I liked the way spears performed

........Orda