Mobile AP items need a buff
Very hard for AP champions to keep up with all the lethality and out of combat movement speed from the assassin updates.
Ludens Echo and Lichebane are super champion specific and Ludens doesn't scale well into the endgame.
Swiftness boots nerf didn't help, and mobility boots dont fit when sorc boots are mandatory for certain champs.
Maybe movement speed needs a rework to stop it from multiplying with out of combat bonuses and abilities to balance out movespeed compared to other champs that don't have it. (Percentage scaling)