Concerning Sion's upcoming buff
2hp to 3hp for kills is nice, really really nice.
Although i would rather see something else in all honesty,
Why not take this as an opportunity to solidify a niche for him, tank wise, with the new hp stacking keystone all tanks essentially become
.
And quite frankly just stacking hp, while nice and fun and all doesn't really give him a niche as afar as tanking goes.
Enemy team has Mages/casters you can pick
or
They have AD or auto attackers pick

this is jsut a few examples of coarse but they all have a tank niche, some are good all round tanks vs mixed damage because they can up both resists some have attackspeed slows some have healing gated through abiliy casts
gets plain old health
Personally i was thinking of doing things a bit differently
Making his W passive grant additional effects, and i thought up a name for it Cold dead flesh He gains X% of his farmed health as
- Attack speed slow on being hit ( cold dead flesh slows you down ) 1%
- Flat reduced damage after resistances ( cold dead flesh does not bleed ) 2%
- Additional base health regeneration ( compensates a bit for his high health values for reasonable regen time) 1%
This would give him a niche vs smaller amounts of damage like bleed effects and on hit damage, but won't really help vs harder hitting damage other tanks have high base resistances or innate abilities to help with that Sion however does not
This will give him a little of that old passive effect back making him tougher vs smaller amounts of damage like dot's and on hit effects.
That being said i will settle for the extra health
Oh and one more thing, i would love it if his Q damage reduction vs minions would scale up to dealing full damage again by level 18 i understand the necessity in the earlier stages of the game but it becomes quite a hassle when minions start leveling up