Kog could use a Shy level rework

Barring an inevitable VGU, Kog could use some tweaks. Not because he's bad, mind. Quite the opposite, really. See, given that Kog does damage and nothing else, the only way to make him an attractive pick is to make his damage so overwhelming that it reaches frankly unhealthy levels.

See: Machine Gun Kog.

So what Kog needs are some things that aren't damage. Or at least are things that aren't his damage.

Because Kog already has something like that in his kit, the resist shred on his Q. So why not focus him more heavily on amping allied damage instead of just buffing his personal damage until he's flatly oppressive?

P - Always Hungry: Kog'Maw is healed for (percentage) of the OnHit damage he deals.

But why? With even greater focus on sustained damage and managing his cooldowns, Kog needs to be able to stick around in combat to make full use of his new Q and Ult. Giving damage vamp on his OnHit damage would prevent him from getting too out of control in the lane phase while giving him solid in-combat sustain once he has a few OnHit items under his belt.

Q - Caustic Spittle: Kog'Maw enhances his next basic attack to shred (flat value) or (percentage) of the target's current resistance, whichever is greater. This resistance shred stacks (addatively for the flat value, multiplicatively for the percentile value). Basic attacks reduce the cooldown of Caustic Spittle by (amount). Additionally, Caustic Spittle's empowered basic attack applies OnHit effects twice.

But why? We're rolling both parts of Kog's Q into a single ability and scaling back the up-front burst. Using a mechanic similar to Shy's Twin Bite allows Kog to sort of break the attack speed cap again, though in a fashion that is much easier to balance for since both mana and cooldowns can be factored into the equation rather than just 'press W and murder everything'. Kog would be able to apply his Q multiple times to a target, stacking up the resist shred and rapidly softening up the enemy front line for his team to destroy.

W - Bio-Arcane Barrage: No real change here, except probably reducing the OnHit damage Kog's W deals. With more power being invested in his other abilities, his stack-check button doesn't need to be so strong.

E - Void Ooze: Kog'Maw spews an ooze ball at a nearby enemy unit, slowing them heavily for (duration). When the duration ends the ooze ball detonates, slowing all nearby enemy units and spreading all resist shred from the primary target onto them.

But why? Rather than a giant slow field, Kog gets a tool for spreading stacks of resist shred and dealing with mean divers trying to get up in his face. When Void Ooze pops, ALL resist shred applied to the primary target goops up everyone else nearby. This makes it VERY dangerous for softer targets to get close to an afflicted Tank, otherwise they'll eat resist shred equal to 20% of the Tank's defense or whatever the value might be. All of these factors together help Kog single out hard targets for his team to focus down.

R - Living Artillery: Kog'Maw fires a projectile at long range, dealing minor magic damage to all enemy units in the target area after a short delay and afflicting them with Free Food for four seconds. Free Food reveals targets and grants all allied basic attacks against them bonus magic damage OnHit equal to (percentage) of their current HP. Living Artillery's impact damage is massively increased against targets below 25% HP.

But why? Kog's Ult is pretty terrible right now. It's still a shitty poke and it's also a shitty execute. Riot wanted to give Kog a reason to Ult healthy targets, but they failed on all counts. The new Ult debuff meshes much better with Kog's new theme of amping allied damage while also giving Kog a great reason to Ult healthy targets. To gain vision and access to the %Current HP damage. That %Current HP damage, in turn, helps to quickly gnaw the afflicted target into Ult execute range.

So overall?

Kog would be losing a ton of flat base damage. The damage from his Passive, the damage on his Q, the damage from his E, and most of the base damage from his Ult. We're talking easily about 800+ burst damage that would be going down the drain. Instead, he would be much more heavily focused on his ability to soften up targets for his team while providing a frightening source of sustained damage. Kog would be a great pick for teams that are low on damage and high on utility (with Kog serving to drastically increase their damage) or on teams looking to decisively remove hard priority targets. Because Kog would now have five major balance levers (his passive sustain, his resist shred, his %Max HP damage, his slow, and his %Current HP damage) Riot would have way more tools for tweaking his balance state than they do right now.