Back the hell off my Rylais, and check your mobility creep...

Aside from all the new and updated champion kits, masteries, runes and neutral buffs, almost every AD item has either flat movespeed or a movespeed active/passive

A few examples

So like, how can you justify taking away the only means of dealing with such bullshit?

if gets nerfed most AP mid lanes will likely never leave their turret let alone their lane due to the constant threat of getting chased/caught out from the most ridiculous distances.

Right now(with proper vision) a mid laner with Rylais can at least take a few steps away from their turret knowing they can slow an assassination attempt just enough to hopefully get assistance or return to safety, but any nerfs to the item will make this pretty much impossible.

TLDR: A nerf to Rylai's will restrict mages to there lane pretty much the entire game, more specifically hugging their turret all game. If Rylai's needs a nerf, mobility creep needs it first.