I rarely reply to threads like this but this time I really feel that it is necessary.
Armor plates are not a good idea and there is absolutely nothing which could change my mind.
I have been with the game since 2014 I think and put some money into it but if those armor plates go into the game I am out for good. This is completely the opposite of what I want from the game and of what I would expect from a WW2 game. I will repeat this again because for me personally it is the most valid point in this discussion: This armor plate system does not fit the theme of a WW2 game. Period.
There have to be other solutions, other games solve this situation too without armor plates.
I think it is absolutely necessary to remove heavy set, it should never have been in the game. All players should have the same chance to die and take damage.
I think the easiest solution to this would be:
Increase the damage a bit for starter semi auto rifles.
Maybe add SMGS very early as unlocks, maybe add a new starter tier SMG set which is available to new players immediately.
That is all.
That is 3 simple steps to do compared to an endless list posted by @Reto.Stenum
Additionally you could also give new players basic hand grenades.