Reddit reviews Legion versus Phalanx: The Epic Struggle for Infantry Supremacy in the Ancient World

There are two similar approaches I like for this for this, both from dice pool systems:

1. Burning Wheel uses a table that lists out advantages by weapon size. Weapons of equal length don't have any advantage or disadvantage against each other, but weapons of different lengths have a +1D or higher when used in a situation that advantages them. For example, a spear has a +4D advantage against a dagger initially, but the dagger gets the +4D advantage instead if they manage to close the distance with a specific Action.
   
2. The Riddle of Steel and its derivatives use a simpler system: The longer weapon gets a +1D advantage to both attack and defense, and the shorter weapon gets a -1D disadvantage to attack, at the start of an engagement. However, if the short weapon user scores a successful attack then they negate their disadvantage and the long weapon suffers a -1D disadvantage to both attack and defense since it's too cumbersome to parry with at close range.
   
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   As for the roman vs phalanx argument: Not only were the roman formations much more flexible than phalanxes, but they were better equipped as well. Myke Cole had a great book on the topic: https://www.amazon.com/dp/B07FXNNWBT/ref=dp-kindle-redirect?_encoding=UTF8&btkr=1

Myke Cole (Twitter) is a fantasy author that is also an ancient military historian. He wrote a book called [Legion vs. Phalanx] (https://www.amazon.com/dp/B07FXNNWBT/ref=dp-kindle-redirect?_encoding=UTF8&btkr=1) that is in depth review of six battles and why the Roman Legion was superior to the Greek Phalanx.