The only thing I don't like about Blade of the Ruined King is the current health damage, beyond that the life steal and active, and icon are pretty cool. One of the disadvantages of stacking health over armor is that life stolen isn't mitigated, so life steal ends up being rather effective against such a defensive route.
I'd rather see Kitae's introduced at the same time as Blade of the Ruined King then see madred's again, it would allow you to build up against health stackers the same way you build up against armor stackers, via comboing 2 items that help counter a specific type of defense rather than solely relying on 1. Kitae's and Blade of the Ruined King would average out to 4.5 max health shred with each attack as well, which doesn't strike me as very abuse-able in the overpowered sense. Kitae's 30 AD and 40% AS are considerably cheaper than Madred's 40 AD and 40% AS as well, which was really the main draw of the item in the first place.