I like the idea of backpacks having armor, but the backpacks would need to have a flat armor value.
To make it vary based on whats inside would be too much to handle.
Ah yes, this would be interesting, however as said by NarcolepticHound, “flat armor value.” I personally own a backpack that if I wanted to I could slide an armor plate in there. Having the ability for military (or any) backpacks to be “reinforced” would be wonderful, could have a slot specifically for that or some sort of option to “attach plate”. Either way though, adding said plate would reduce the storage of the pack.