User blog comment:Myself v1.0/HP over defenses? O rly?/@comment-108.167.24.27-20130124170900/@comment-72.22.168.66-20130124214623

The actual reason we see so many physical damage mids is because of the penetration changes and the Black Cleaver. Combined, these make nearly all physical casters very strong, or at least far stronger than others. It was for this reason that champions like Lee Sin, Talon and Kha'Zix were nerfed. In the past, physical casters were extremely easy to counter because of the far more numerous armor options compared to magic resist. However, Black Cleaver allows them to practically ignore large amounts of armor, and the Magic Damage champions do not have the same equivalent to reduce enemy magic resist.