Bronze Lorica Segmentata

[Tarbicus]

If you want armour representations that are more likely to be accurate, look at the Adamklissi Metopes (no segs, though). Trajan's Column being in Rome, Italy, the sculptors probably never saw a real legionary wearing armour in their lives.

The numerous plates that you propose being on the chest makes the legionary's chest more vulnerable. I haven't seen found upper shoulder guard plates about 2cm wide, either.