I do not understand why Riot is nerfing Rylai's Crystal Scepter in the first place. It is something for mages to get some health, if they feel like that could help, 100 AP, always great, and a slow, that depends on your champion if its awesome kiting or whatever. I wasn't around when Zyona's was 100 AP but Morell, Luden's Ekko, Rylai's, Rod of Ages (after 10 minutes) and Deathcap are the only 100 AP or more in the game. Nerfing all these items means all mages are getting a nerfed. For the most part, the reason why players go for items like Hexteck Proto-belt is for the active or Void Staff for the magic pen.
I like mages, from mid lane mages- Ahri, Syndra, Xerath, Cass- to support mages- Zyra- to the jungle- Diana. I am a player that has been playing with AP characters so much, I memorized a lot of the items, stats, names, passives, cost and active (Though not all). I will see that this will hurt a lot of mages. Seeing how we are in a Assassin Meta, Mages will lose their burst combat the burst assassins. Maybe Riot wants Assassins to be the king of bursting and wish to destroy mage burst. Why? I do not like these changes.
Getting any AP item that is not 100 AP is usually because the passive/active is better than just a flat 100 AP
-- Void staff- Magic Pen
--Liandra's Tourment- Burn for tankier targets as well as magic pen
--Proto-belt- Active
--Zhonya's- Active
--Linche Bane- Passive as well as other stats
A lot of the 100 AP items usually does not have other stats that are beneficially. Say Luden's Echo- 100 AP is great, 10% ehhh, for champs like Cass works but immobile mages... ehhh. The passive is usually not worth rushing it as a first item as a mage. Rylai's has a slow that does not work on all mages, especially on aoe champs. The health depends on the champ but of you are meant to be safe, then why get the health?
Riot are buffing Assassins and now they are going to nerf Mages... Yay. Assassins in the mid lane all the way... I guess.