Converting all legionaries' armours from hamata to segmentata? Tha's a nonsense!!!
It's proved that the lorica segmentata had never been the widely standard imperial armour. And that's why the concept of "standardization" as in modern age was completly unknown in ancient age.
Romans have a general idea of a "panoplia", a general type of equipment for heavy infantry, but they didn't ever said "ok guys,all legion must have this shoes,this type of scutum" etc.
Exceptions and variants possibilities were common: roman chose their equipment depending of what type of enemies they have to face.
in particular:
Lorica hamata NEVER disappeared in roman legions.
Let's take a look, for examples at the Tropaeum Traiani and in the Asdamclisi Musueum: there you can also see legionaries of Trajan wearing lorica squamata!!!
Later, lorica hamata re-became more common in legions than the segmentatas after Septimius Severus.
"Shiny Lorica Segmentata": the so well kwnon bright steel color of these armours it's an historical mistake: did you figure a legionary that goes into the forest of Germania or in the desert shining like a star in his bright lorica? Romans were not stupid: they protect their armour brunishing them (expecially in north) or cover the steel with other proctections in hotter zone: this prevent them from rust and to be a shiny bastard in the middle of the battle

Another fact: roman legionaries in short pants: now, have you ever be in germania? even in summer? it's damend cold up there! And you pretent to go into the snow in short pants? Are you crazy? legions in nothern sectors use long pants as reported in many forts (regensburg or castra regina for example)!!!
now,scutum: all legions equipped with rectangulars scutum? not at all: when the authors of trajan's Column in Rome have to search for models they used the pretorian Guard stationed in the capital,but that does not mean that every roman legions was equipped with rectangular scutums. there was a great variety of them (mostly oval like in republican period).
helmets: you can become crazy in knowing how many type of helmets exist from the Imperial gallic to the italic!!!
Now, stop talking about "standard equipment": for Roman period is a nonsense!!