So? The reason they have more armor pen items is because there is more armor naturally then mr, when you look at the magic pen build for mages they can literally reach true dmg on ppl with no mr. That never happens with assassins because ppl will always buy armor items, because they must build some armor to stop adc's or ad assassins or ad jg's. Their is more armor in the game then mr naturally so more pen items.
Honestly thats a subjective view tbh, but lets look rylais is a bad item thats true, it should be buffed in some area. Rod isnt bad it is core on alot of mages because it provides hp which is literally the best defensive stat in the game.
Almost forgot about these should i switch the rylais for that too. That also sounds balanced to me, you have to give up some power in order to survive seems reasonable balance wise. Are you trying to compare ad assassin builds to mage builds? You understand that assassins need to be stronger early game right? They are early game champions because they fall off completely late game. Yes sudden impact is for assassins, ASSASSINS in general, fizz can use it, elise, diana, kata, akali all ap so that isnt even a point because they all use it too, they also dont build the items ad assassins build and preform well so what is the point you are trying to make, they get more magic pen too?
Ok and once you get a void staff you can chunk through tanks and burst down squishies too, man it is like itemization in the proper sense actually helps champions in a way? Just because you get armor doesnt mean you are invincible that is the way the game is.
Yes he will win if he is in range, which makes it your job to kit after he gets in range, dont use cc before he uses his mobility and punish him after he does. You have to understand mages and adc's are countered by assassins, meaning you should lose unless you play right early game. If you use you zhonya's before zed ults you lose, if you miss your cc before zed uses his ult you will lose. It is the basics of the game you have to figure out how to outplay the game will not give you more options because you can't figure out what other ppl have.