AP and AD Kog Maw suggestions
Kog Maw has been in an odd spot, changing as metas do, and the inderect nerfs with item and champion changes recently is going to drop him out mostly now. I'd honestly classify him as unhealthy at times. One particular build is tanky kog maw. Here's a few thoughts on him.
For AD Kog Maw, he's been receiving inderect nerfs with tweaking the on hit items like ruunans and botrk. This nerfs tanky kog quite a bit. Also the fact that Lulu dropped out in power affects him a lot. This is where I place my suggestion. Add a base cool down reduction on his Ultimate, like sona, that affects his W. This way his W cool down is lower by his level, not his W rank, so that he's not so oppressive In the early game, but give him more uptime to poke late game. 9 seconds of downtime for his W feels horrendous if you make a mistake late game, and it's too big a window for divers and assassins to punish you. It should be fine now that tanky kog maw should fall out.
As for AP Kog Maw, the Nerf on his E was necessary, but that dropped him out completely. Here's some of my thoughts when I play him.
AP Kog Maw can be best compared to Lux in every single way, but with less burst, which makes him very inconsistent. Ever since the Nerf on his E to tone down his waveclear, he's been lacking in burst damage, which completely sucks because you're very very fragile. If you don't burst down your opponent you're dead, literally just like Lux. Do your combo and execute with your ultimate. But you're missing the bind, so you can follow up, or simply run away. What happens when you miss your skill shots with Lux?, youre dead, just like kog, except with kog you don't have the burst and cc to survive if you mess up. I'm suggesting an AP ratio increase on his Q significantly, that way he can actually burst down someone, and you can leave your tower to help get objectives on your own. Last time he popped out in OP.GG his winrate sat at around 44%, literally all he needs to keep him in balance is adding burst to him so that he can actually be useful, all he is right now is an execute machine, which means you rely on your team way too much. Doesn't matter how fed you are, if you can't kill someone on your own. That way if you're the only one ahead on your team, you can actually do something.