Balance of deffense and offense

i played LoL since end of season 2 and bcs i was getting a bit bored i started play overwatch then hearstone and after that around christmas WoW. I learned 1 thing. 1 thing that i think league of legends needs. add second type of defensive system for champions and you can use only 1 per game. that system that we are using now has armor and magic resist thats perfect for tanks. for adc and mages there should be different system works similar to verstility stat in WoW. that is it increase dmg dealt and reducing dmg taken. and these 2 systems should be separated 1 from other.