rylais wasnt actually nerfed much for her.
the health nerf isnt that big of a deal. the slow nerf doesnt affect her, since multi hit abilities havent been touched, so her q slow is the same as before.
the item mainly lost ap for her which it makes up for by being cheaper and giving her an earlier powerspike. which is especially important, since she wants to waveclear and roam, so she can build this item quickly for the slow before getting an actual damage item.
rylais wasnt even nerfed in the right way. its still, a problematic item. the nerf should have hit multi hit ability slows instead of its base stats or aoe slows. ranged ap champions with dot abilities and minions are still abusing it to completely disable slower champions without efford.