Answer:
The change was notable and a new weakness was added to the Roman empire.
Step-by-step explanation:
There were two popular kind of armors sets used in the era:
A)The Lorica Segmentata: This one was used more in the replubic time of the Roman empire (one of the most succesful ones) it was really resistant and complete bringing fulll protection to the soldier, at the same time was well divided in different sections, giving flexibility as well.
B) Lorica Hamata: This armor was effective too however it gave less protection to the users, changing the fortified mid section armor, to a more flexible one, it gave more movement to the user, and was effective against melee weapons (swords, axes, etc), however it had a strong weaknees against the arrows.
Due economic and political crisis , on the last years of the Roman empire (where the ilness, resources and invasions were constant problems), the second one had to be used more, due to this, and with the constant battles, they started to present serious problems against long range weapons, and even in one-to-one confrontations, their armies started to be defeated in an easier way.