I would ALSO like his hp interactions changed as well like you mentioned, the upsides to having it (stoneplate/titanic mainly) are far outweighed by the amount of %max hp damage you take because of both of his hp amounts being counted together by all the %max hp damage in the game that I mentioned in other reply, I would way rather lose all that and have his HP amounts treated as seperate amounts in exchange for other, less meta/item dependent things (personally have always wanted the 10/20/30% armor pen on ult rank like was added to pantheon over it)
I would even rather lose grievous on his Q completely in exchange for that and potentially a revert to his Q cd nerf early game since it swung so many top lane matchups that are heavily based on cds, his early game feels too weak for how poorly he scales into teamfights in my experience and you generally have to grievous wounds still anyway with the huge amount of healing in the game you can't afford to rely on your single target delayed skillshot grievous and need chempunk a lot of the times regardless