New 100AP item?

So the Rylai's nerf was pretty decent, but i find when playing champions who want to just buy as much AP as possible struggling a bit more now with only having 3 items that give 100 AP, and one item 120 AP (excluding mejais because you wont get max stacks every single game) . Ludens echo is a all around good item because its stats and passives are good on almost every AP champion. Rod of ages isnt a great item for ever AP champion, but is still great for those champs who do rush Rod. Morollos is basically a must get item if you dont rush a rod of ages, and the CDR is a must if you are planning on getting 40% CDR for a lot of AP mages. Rabbadons is still good.

I feel like there should be a new AP item that gives 100 AP for those champions who dont build Rod. One idea of an item i had is an item that gives 10% CDR, 90 AP, passive gain 1 AP for each seige minion you kill. Max stacks 10. Maybe a second passive or stat to make it a bit more unique? Anyways what are your thoughts on this subject? Rylai's change was needed, but do you feel like there should be a new 100 AP item of some sorts for mages?