User blog comment:ClariS/Why Xerath's Passive is Bad/@comment-5297851-20130317085732

Actually in my opinion, his passive is just is lacking from other AP mids and is just in it's peak since AD mids are currently what's rising in the Meta. Since if you would remember, seeker's armguard was created to boost AP mid's defense against those mid-laning ADs, Xerath already have this way before and is actually a great counter against them AD-mids. But just like you, before I used to question his passive. I ask myself "If most mid laners are AP bursts, then what good would a bonus armor do to me?". Then the AD mid trend arose and it all makes sense now. Xerath's passive doesn't fit the character, it fits his role.