The probleme about ap-itemization

An adc buys only if the enemy team has a lot of tanks that buy armor. A mage buys in literally every single game regardless of what enemy he faces. Some adcs that scale really well with attack speed buy more attack speed. (vayne/Kog'maw) Every mages gets 40% cdr regardless of how well the champ scales with cdr or doesn't. There are different ways of doing ad-damage: onhit dmg, lethality, crit, or just raw ad. Do we want to differentiate between tear + RoD and Morellos? Cause in the end they do pretty much the same thing?

Make raw-ap the general item path of mages. And all other stats: cdr/penetration/defensive stats (zhonya/banshee) situational stats. And if you go for situational stats you get less raw ap instead.