I do not think I am making too extreme a statement when I suggest that phalanxes, as a general rule, get a fairly bad press in wargaming. While the Spartans and Alexander might get nods in the direction of ‘it worked all right, but only because they were odd or brilliant’, on the whole, phalanxes are regarded as being a rather dead end military formation, which only took the Roman legion to find out.
This does seem to disregard the fact that the phalanx, in its various forms, was the most successful military formation in the period from about 500 BC to about 200 BC, certainly in the eastern Mediterranean.
I suspect the main criticism of the phalanx comes from Polybius, who records the destruction of a phalanx by the Romans, partly by bad terrain, partly by the greater flexibility of Roman maniples (Cynoscephale 197 BC, Pynda 168 BC).
Now, firstly, I suppose that we need to distinguish two different sorts of phalanx, the Greek city citizen phalanx, of Thebes, Athens and Sparta, and the peasant phalanx of Philip II, Alexander III and the Successors. The former were eight rank deep (or more, or less) spear and shield wielding citizens (as opposed to slaves), while the latter were Macedonian rural peasants with a sixteen or so foot long pike.
We have regrettably little information about the internal formation of any of these phalanxes, however, so we cannot help but, to some extent at least, lump them together.
The Spartans were, at least initially, a well-trained and articulated phalanx, and they could carry out some manoeuvers. The lowest level unit seems to have been about 30 – 40 men, and they were also divided by years of service. Often, in for example Xenophon’s Hellenika, the ten year class is called out of the phalanx for some reason, often to chase off peltasts (e.g. Hellenika 4.4.16; 4.5.14-15). This does suggest some articulation, some lower level organisation, of the phalanx.
Xenophon also reports that the Spartans could also wheel inward if they overlapped the enemy flank (Hel 4.2.20) and also reverse wheel to get a flank out of trouble (Hel 6.2.21, although the manoeuvre was not that successful). So the Spartan phalanx was, at least, somewhat less than the inflexible picture that we have of a mass of men with pointy stick always going forward but a disaster in any other direction.
Philip and Alexander’s phalanxes were also articulated and thus flexible and, as a result, had to be well trained. Whether the sarisa gave them a huge advantage over the hoplite spear is a bit of a moot question, however victorious the pike phalanx tended to be over the hoplite one. The fact is that they did not, so far as I am aware, meet that often on the battlefield and other factors could well be in play, such as alliance politics and, of course, poorly trained troops. Better trained men tend to win over less well trained, whatever the weapons.
As time went on, of course, things became more difficult. For example, the Spartan army became less and less Spartan as time went on. This was for a variety of reasons, but mainly economic problems meant that there were fewer products of the (somewhat bizarre) Spartan training system available; after Lecutra (371 BC) there were less than 1000 ‘pure’ Spartans available to the army. The centralisation of privately owned land into fewer hands seems to have meant that fewer Spartan males could afford their mess fees, and so could not join the army, and so, despite the inclusion of perioikoi divisions – Lacedaemonians from outside Sparta proper - the number of troops available to Sparta seems to have declined.
After Alexander, of course, the empire he had founded broke up, although the basic tactics of the Successors remained the same. Supported by the wealth of the conquered Persian Empire (there was quite a lot of early fighting over the treasuries where Alexander had put the loot), the phalanxes could continue in pretty much the same way. However, they started to be used as the main fighting force, to crush the enemy, whereas Alexander had used them to pin the foe while he executed the decisive manoeuver elsewhere, usually with the Companions.
As the quantity of pay decreased (that is, alexander’s loot was spent), so did the quality of the trained phalangites. I do not actually know, but I suspect that by the time of Pynda, the phalanx was rather low quality, and so it is hardly a surprise to find it being defeated by a semi-professional Roman army. The fact of the defeat may have nothing to do with the phalanx qua phalanx, but may have more to do with poor training, leadership and contingent events on the battlefield, such as bad terrain and elephants running amok.
So the point I am trying to make is that the phalanx was not as inflexible and vulnerable as we might think. Certainly, hoplites went down to some spectacular defeats to peltasts at for example, Corinth in 390 BC, when a Spartan mora (brigade or division) was heavily mauled by Iphikrates (Hel 4.5.11-8), although this possibly has more to do with Spartan overconfidence and bad terrain rather than any inherent superiority of peltast over hoplite.
The problem is, of course, that modelling the formation in a form which shows the flexibility of the phalanx is a bit difficult. DBA, for example, gives hoplites +4 and auxilia (peltasts) +3, but recoils both if they lose, which sort of gets the result desired by only by ignoring the dynamics of what actually happened. I suppose that the +1 for being uphill helps the peltasts cause, but it does not seem to reflect the fact that peltasts often moved parallel to the line of march, up a hill, throwing javelins and generally bogging the advance down.
Perhaps there is no good way of representing this in a wargame (am I tilting at windmills again?), or, possibly, we could argue that the major battles were not encumbered by large quantities of peltasts doing their annoying skirmishing thing. But then we land up in a whole other load of historiographical problems to do with writing the events about important people, not non-citizens like those wretched lightly armed men.