Can mages get a second option for armor?

Mages have 50 armor from a zhonyas hourglass (unless they go ninja tabi but who does that). That is it. 75 armor before runes and masteries. They also have 3 types of flat Magic pen with one %pen for a potential 50 flat | 35%. AD champs have 2 kinds of mr totaling 85 mr. Plus 15 mr if their support gets a , +25 if they have and another +60 if they get . Totaling 185 potential mr before runes and masteries. AD also have a lot of armor penetration with (duskblade). so 40 flat pen. up to 30% armor reduction as well as 45% bonus armor penetration. so a 75 armor mage will be reduced to only 41.25 armor with the upgraded Last Whisper, then to 28.875 armor after black cleaver and then by 40 flat armor pen making them have less armor than they naturally scale with. And there is no compromise from the AD champion for doing this build. they get 290 bonus AD from just these 5 items. along with 50 mr, 30%CDR, 300 hp, 5% ms, one active, 4 passives (lifeline, rage, executioner/giant slayer, and nightfall), which one is an execute, a shield, a movement speed buff, and either a damage buff or applies grievous wounds (if the target has more max health than you).

I have an item suggestion that i posted already a while ago because I felt that i should at least try to help solve this issue by providing a suggestion. http://boards.na.leagueoflegends.com/en/c/skin-champion-concepts/Ng4QQ669-item-an-ap-version-of-qss