Why should i buy ap on akail?

Her ad ratios on passive and Q better. E is physical damage only with no ap ratio. Ult has + 50% bonus Ad but the ap is only missing hp so building ap just for that seems silly and you have to wait 3 sec till after you cast r1 to be able to cast r2. wave clear is better, objective damage is better because your non empowered auto do damage. Duskblade synergy with shroud is insane. Titanic+Sterag synergy and a wider (and better imo) selection of items that dont all have mana attached.

To me it seems like ad tanky akali does more damage AND has better survivability than the squishy ap alternative so im wondering why even build ap outside of a gunblade? was the purpose of the rework to make her an ad focused champ because with the numbers the way they are that's what she is.