[Phalanxes] What am I doing wrong?

[A_Dane]

I'm wondering if this is the case too; I leave them a lot wider than they are deep (the default they appear on the battle deployment) for maximum frontage. What I worry about is leaving gaps between them where the enemy can filter in and threaten their morale ("Concerned about exposed flank").

Can only advice you try it for yourself. In some situations i find that a wide line is better than a box, but when fighting other phalanxes, being slightly more dense seems to give me the advantage.