So yea riot about Sion W
If you wanna reduce the HP gains at lower lvls that's fine, but i hope to god you don't forget that Sion is a tank that needs to commit for pretty much everything he does and has right now the 8 lowest lvl 18 HP in the game, below the likes of Sona,lb, adcs and all that.
But anyway i hope you end up giving him some (real)compensation buffs and up the hp gain per lvl a little, not much but at least not 1783.6 hp when Lee win has 2015.8.