I was trying to play the game as close to historical reality as possible, and since they didn't do it that way back in 190 BC, neither did I. In a related point, once a unit goes into combat, its a real bitch trying to withdraw it.
On the do as the Romans do comment, my impression is that the Romans and others tried to keep a continuous line and fight it out in a slugging match, rather than maneuver individual Centuries and Maniples like they are Maseratis. I know that when I do that it does seem to confound the AI a bit, but eventually a free for all does rear its ugly head.
I am really chomping at the bit to play Alesia, but I have 1859 Risorgimento Italians to paint.
Ciao (or is it Ave!!!), Colonel Bill