Christos - the thickness of the armour plates is a common error on models. It's even worse on 54mm figures! It would be far better if the sculptor simply modelled a plain and smoothe chest/back and then scribed in some lines to represent the armour plates. They really were only a mm or two in thickess - there are enough of them in the archaeological record to be sure of this. I assure you that, even if it 'looks' OK - it isn't. The Corbridge finds make this very clear - for once we have complete sets of something that we can be sure was actually used by the soldiers.
It's a curious fact that the contemporary Adamklissi monument in Romania, which was raised after the Dacian Wars, does not show a single instance of lorica segmentata being worn. All the figures represented on more than 50 panels wear only hamata (mail) or squamata (scale) armour. The Trajanic Column in Rome, however, shows the legionary troops wearing this (segmentata) armour while the auxiliaries wear mail or scale armours!
There is no real evidence to suggest that the front rank of a legion wore the plate armour. Since each soldier had to buy his own equipment, weapons, clothing, etc., there is no chance that we would see such a 'uniform' thing as a complete rank of men wearing only one type of armour.
There's another fault on this model that I've only just noticed. The sword is the wrong shape in the blade. By this time the tapering legionary sword (the so-called Pompeii type) had been replaced by the ('Mainz' or 'Fulham') type, where the sides of the blade were parallel and there was a point that was an obtuse angle, not acute. Presumably this was because the thin point broke off too often in combat. The wavy edged blade shown in this model is neither - more fantasy!