All in all. This Armour upgrade for Osteehr infantry will most definitely deal with the issues that everyone experiences when playing Osteehr, survivability. To take less overall damage will surely make a difference. That I am certain of!
Grenadiers don't have survivability issues versus small arms. They have survivability issues vs AoE weapons while clumped behind cover.
That's because, as a four man squad, they clump together tighter. This is an
advantage versus accuracy based weapons because you can fit them all behind cover.
The drawback is it's also easier to fit the whole squad into the lethal AoE radius of a tank, grenade or mortar.
Armour won't do shit against that because it's not going to bounce a tank shell.