A thin line of spears

[Doug-Thompson]

But then, the historical Ancient phalanxes tended to be huge affairs of thousands of men in a single rectangular block hundreds of meter wide and up to sixteen ranks deep. The ones in Rome don't exactly compare...

And

The real problem we have with the Phalanx is the inability to create a solid unbroken line. The natural gaps between the units always makes things worse.

The only way to get the proportions close to correct would be to link multiple units in an unbroken front, in my opinion.

The Macedonian Phalanx of Roman times was deeper and, frankly, less maneuverable than Alexander's

Say --quite arbitrarily -- that the typical hoplite formation of 80 (large unit size) is supposed to be part of the "classic," somewhat flexible phalanx a la Alexander, and that the 120-man unit is supposed to be part of the newer, more dense Macedonian model with longer pikes.

Alexander's phalanx was 16 ranks deep and 256 files wide. This gives a depth-to-front ratio of 1 to 16. This contained (at full strength) 4,096 troops.

Take five large unit-size hoplite formations at their default depth of five ranks. Put them end to end. This results in:

A group five ranks deep and 80 files wide, a perfect 1 to 16 depth-to-front ratio. It contains 400 men -- a 97.7 percent-pure little 1/10th scale model of the classic Alexandrian phalanx.

In my opinion, phalanx should not be a special ability for one group of 80 or so spear types but a special group formation, a "hard" grouping that only phalanx-type units can employ that eliminates the gaps between units. The hoplites can "ungroup" if they need to change facing rapidly, moving the individual units, and "regroup" when facing the desired direction. There should also be a rank bonus maximized for a depth-to-front ratio of about 1-to-16, or deeper in the case of longer pikes.