Armor? Does it help now?

Last Whisper allows for AD champions to ignore roughly half a tanks bought armor. Then there's flat pen / % pen in masteries, a large number of easy access to flat pen items as well.

Armor is Useful https://qph.is.quoracdn.net/main-qimg-60410796fdd1176dbb93a8386b390551?convert_to_webp=true

Armor is pretty effective, but if you don't have a high health with it then it doesn't feel useful.

mr and armor once used to be the superior defensive stats. that was before riot changed the formula for flat armor pen to apply after % pen.

they realized that resistances being the main defensive stat creates clarity issues. champions who bought resistances over health looked a lot less tanky by their health bars than they were.

so they changed the game up and made resistances worth less and made health the main defensive stat.

then they realized they dont actually want anyone to be really durable and overloaded the game with % health damage. then they nerfed resistances again, then armor, then reistances, then health some more, attack speed slows somewhere in between, then they introduced even more armor and magic pen.