I think it is time for a new 100 AP item

We just lost -20 AP on Morello, and the "new" mana items have 80 AP (except Seraph's at 50). Luden's one of them, so we now only have the new Spellbound Orb as the only instant 100 AP item in the game. I don't get why we can't have more of them, is it balance-related? Let's see a more or less standard build in the new system. Boots + First Mana Item + Spellbound Orb + Liandry's Torment or Morello's Cursed Tome + Void Staff + Zhonya's Hourglass. As a mage you obviously need mana. As a magic damage dealer you need penetration so Void Staff is a given, even with its lowered AP. Liandry is going to be amazing on every Battle Mage, specially those with dots. Morello's is the only flat magic pen item in the game other than boots. Zhonya is core on every non-Artillery mage for its play-making potential. See? Almost all of those items are required. The point is a new 100 AP item wouldn't hurt balance unless it's flat out overtuned, since it has an opportunity cost with other options; trading either sustain, durability or penetration over AP. Next patch we will lose AP on every non-Rabadon build (which is still almost unbuildable, since you did nothing for its humongous cost nor horrendous build path), so I think it should be looked at.