The Makedonian phalanx -- why such depth?

[Paralus]

My answer: On the evidence we have, the best answer is that Greek and Macedonian files, whether 8,12 or 16 deep ( and rarely 10) did not normally fight as files, but rather as half-files, thus the Macedonian phalanx generally would have fought 8 deep...

The most important activity of an army is fighting a battle and, hopefully, winning. If your statement is correct then the most important officer at "platoon level" is the half file leader. Seems Alexander's army did not have such - as far as I can recall. We have file leaders (and closers) but no attested haf file colleagues.

You insistence on the one line in Xenophon's Anabasis that the fighting depths of Greek pahalanxes was four is a stretch of one single line. I might as well state that Thucydides' mention of Spartan "felt caps" at Sphacteria means Spartan hoplites always wore same, as did the other Greeks. One mercenary army; one place and one pre-dinner display drill. Xenophon himself later states that the army fell into battle order (in another drill at Byzantium if I remeber) eight deep. You hang much wedding tackle on a single line...