Ave, Caesar!
I will try to answer your question; however, the answer really involves a number of nuances to the rules that encourage good behavior, rather than a series of proscriptive or prescriptive rules than enforce good tactics. First some philosophy: I think that rules should allow things that are physically possible, even if they are bad tactics. The rules should provide penalties for bad tactics not preventive measures to guard against them.
So what encourages good behavior?
- First, units (bases) are allowed to turn at the beginning of the move, but then must move in a straight line. Keeping linear formations makes it difficult to enemy units to get desired flank attacks on your formations.
- You must have 1.5 inches (40mm) between friendly bases in order to enable units to move past ("through") each other. Non-linear formations will often confound this.
- Units (bases) drop back 3" if they do not win a melee (there is no "locked in contact" melee result). Putting two lines closer together or having goofy looking formations can cause all kinds of cascading effects, including morale checks and other things.
- Morale is rolled by "brigade." (We're not sure what to call this first collection of units, since it differs by army and period.) In any event, a collection of four to six units can fail morale and withdraw at the same time. This makes it VERY important for a player to line up brigade in depth to plug holes.
- Units drop out of melee if they don't cause more damage to the enemy than they received (there are nuances here, but I'm only hitting the tops of the waves). This makes it important for players to keep a second rank, even within the same "brigade" to plug holes.
- The Romans have a special, optional rule that enables them to switch the front and second ranks of "brigades" in an activation. Again, you need to be in mostly linear formations in order to invoke this rule.
In reading back through this, I'm not sure that the above explanation fully answers your question. Suffice to say at this point that players are rewarded for keeping reasonably orderly lines.
Buck
