Riot needs to decide what they want Kog to be
Is he a hyper-scaling centerpiece Marksmen? Then give him some actual scaling on his W.
Is he a mid-game power spike champion? Then improve his base damage some more.
Because right now Kog has a shitty early game, spikes at two items, and then drops off hard. He has all the worst characteristics of a hyper-carry like Twitch and a mid-game domination champion like Corki.