After the mana changes during the mid-season patches it really suck I can't go Archangel + Ludens

Luden's used to be a wave clear item that you bought after your first mana item (Old Morello or AAS). When I played AP Kog'Maw I would rush Archangel's staff into Luden's Echo for the mana sustain and wave clear. Now, I can't go both because of how inefficient it is CDR wise. They've really made it clear that you can either go AAS or Ludens but not both. After your first big item you HAVE to go penetration because all the other mages rush Sorc + Oblivion orb. It's just sad that I have to always take a cookie cutter route with my builds. There is very little leeway.