Brocen Cresent from the 1st day of its existance nottified its fans that the Roman roster is more or less one made for game play.
Anyway....
Archers in general were unarmored.Only in the peak of Macedonian Dynasty (Nikephorus Phokas reforms) archers and javelinmen had some simple and cheap body armor.
Archery was not the strong point of Roman warfare. That is why Romans (byzantines) use to hire archer mercenaries. A very good addition was Turkic origin warriors that embrased Christianity and became part of the Roman society. They had a number of names such Murtatoi or Turkopulla (the last name means children of Turks).
Saracen archers (also from arabs or islamic persians) were recruited under the name of Pharganoi.
Tagmatic forces in BC's timeframe were in decline.
Instead Latinikon (German,Norman and Hungarian knights), Scythikon (warriors of Cumans,Pechenegs,Seljuck,Oguz etc) were some of the units that replaced Tagmatic forces.
Conclusion.
Romans had weak archers. If a player needs better ones he/she must recruit mercenaries.