Why does Kog'maw have to have the worst early game in league?
Is it because he's a hypercarry? I guess all hypercarries are completely devoid of any kind of self defense/peel/utility/trading ability...
..oh darn.
All of those champs have access to dominant late games, but have at least one thing in their kit that keeps them from getting royally shit on by everything that moves. Be it waveclear to keep from getting pushed in, or cc to self peel, or mobility to disengage or engage. Or maybe all of them in the case of 
What does Kogmaw get for surviving into late game? Massive DPS for sure, along with global focus, and an attack steroid that now punishes him for trying to orb walk, or even reposition. He is a hypercarry for 6 seconds at a time, and if you force him to reposition at all, his dps is hurt vastly more than any other ADC.
Thing is, other hypercarries arent fully reliant on timed steroids. Even
still has the advantage of range when her Q is on cooldown.
Hell, some hypercarries are dominant from
the moment
they step into
lane
due to hilariously overloaded kits.
Kogmaw's early game is far more pathetic than any other hypercarry, yet even when he scales, he is much more vulnerable than any other adc, and his damage can be hit hard by simply staying on top of him. If he isnt allowed to use his W like a channeled ability, then he wont be outputting hypercarry levels of damage.
Give him some kind of ability to freaking trade or poke, or clear waves, or escape. Maybe give him some actual damage back on his W in early levels so that it hits harder than a caster minion. I shouldnt need 4 items for my primary damage ability to actually deal perceptable damage. Maybe give him some mana sustain so that he doesnt go oom with 3 spells since you decided to give his W a mana cost again. Or maybe if his ult now costs more mana, give it some actual damage instead of having it hit like a gentle breeze on anything with more than 25% hp.
Kog's old W used to at least give him a way to poke back at people, and his ult finally gave him a little bit of an edge after surviving 6 levels of being a total wimp.
TLDR Kog's rework sucks balls unless you have an army of tanks to babysit you. His damage is more conditional than other carries, and he has less ability to defend himself than any other adc, all while having the worst early game out of all adcs.