You know, I'd be 100% fine with a cheap Rylais (Verdict after playing with it on the PBE)

If Mordekaiser had the stats to actually be able to: A) Build it without gimping his late game B) Have it as an OPTION C) Be able to rush other items first if he so desires

As things currently stand with the item Mordekaiser's reliance on it really showed through with those changes. His late game scaling was impaired, his abysmally low base stats finally shine through and he struggles to do his job.

BUT: I feel the Rylais changes were the right ones, making it an option you consciously build and it being cheaper gives Mordekaiser a decent rush option without being starved if he doesn't manage to acquire enough gold to get a Needlessly large rod.

It does come at Morde's expense though as like a Drug addict he's been denied his fix.

Rylais having become less oppressive and Morde's power having been lowered does warrant some changes for the Iron Revenant though to really make him a decent pick until his VGU.

Rylais slow being halved Mordekaiser struggles to keep up with his enemies and do his thing, making him fall flat since he relied 100% on the 40% slow. >Buff his base MS to fall in line with the other Juggernauts= 335-340

Lower stats, especially health->Late game fantasy Even though Mordekaiser gets his item spike earlier he struggles from his item build falling off late due to it being cost inefficient. It wouldn't be a problem if Mordekaiser actually had LATE GAME SCALING like every other Juggernaut who get tremendous benefits from every level up and all average between 300 and 600 more HP than Mordekaiser >To solidify his late game fantasy Mordekaiser might need some small base stats adjustments to make him fall in line with other Juggernauts and their power curves. The nerf to Rylais HP and to some extent Steraks really hurt him and it being a rather cheap/effective yet cost inefficient item makes him rely more on his base stats, which are laughably weak. Ergo some buffs to his base line tankiness could be in order, Maybe around +200 hp to put him close to the other Fighters (Even Aatrox has 1980 base hp!!)

Tl;DR: The Rylais changes are for the greater good; They fix the abuse cases and make Rylais an option for champions who like the slow it provides and its stats while making it a conscious choice. It comes at Mordekaiser's expense though and he'll be in dire need for some compensation to give him back the power the Rylais nerf had taken from him.

In the end he'll be healthier due to no longer being 100% reliant on Rylais and would actually open him up to other items and build paths like early Gunblades if he had the base HP to actually allow an entirely offensive first item.