Against that, it would have made it a bit incomprehensible to the U.S. audience who are more used to companies, battalions, and regiments. While I am familiar with Roman legion organization, the average war gamer would be totally lost with those terms. Currently, with my World War 2 class, we spend some time going over what unit terms mean in World War 2, as the students are pretty much lost in that area.
I am not a fan of using what I call obsolete terms in writing, and those terms are pretty much obsolete.