Failed rework: Kog'Maw
Champion is complete garbage after his little rework, the buff he got on his W didn't help at all.
He's a late game champion, OK, that doesn't mean you have to completely remove his early and mid game from existence to make up for his machine gun W that won't actually be relevant until 40 minutes into the game.
It's like playing farming simulator 2016, die a handful of times along the way because you're so immobile and always OOM, and maybe if your team didn't FF yet you'll be able to score a few kills before the nexus goes boom.
Get rid of his AP scalings (He has a** ONE PERCENT** popularity rate, AP kog is not a thing and won't be a thing), take off some of the excessive attack speed on his W, remove the unnecessary mana gating on his ultimate (which is now ONLY an execute), greatly reduce the mana cost on his E and increase it's damage.