back in patch 5.4, mordekaiser's ult was changed to not give him ad

under the guise >R - Children of the Grave AD MORDEKAISER ISN'T A THING Enslaved champions grant Mordekaiser +20% of their attack damage and ability power ⇒ +25% of their bonus health and +30% of their ability power

now suddenly he is? with his e apparently scaling with his total ad, and his pigeonholing to a duo lane bot (which is either going to end up with morde being god tier, or garbage tier) what exactly is the plan with this champion? is he ad now? is he still ap?