@Meddler Please consider balancing Kog'Maw as a state change champion like Gnar.
I don't know if I'll get a response, but I'm really hoping because I know you worked on Gnar. I'm hoping this description makes sense.
I think the reason Kog'maw's season 6 rework failed, and the reason his current balance changes haven't felt good is that you're balancing him around his auto attack steriod almost exclusively. This was further shown with the last update which nerfed his void ooze base damage and ratio massively and slightly buffed his W autos.
I think the reason that AD Kog was so much fun in season 5 and before is that he had a team-wide phase change element to his kit, much like Gnar.
With his W is on cooldown he plays like a poke ADC / artillery mage that occasionally uses TF procs. His entire team has to support this by acting like a poke team. This is like when gnar is in mini form and has to poke and kite with his boomerang. A team with a mini gnar shouldn't act like a team fight comp. They have to kite as a team. The same goes for Kog'maw in this phase.
On the other hand, when Kog's W is up, the team needs to lock down the enemy team and start fights. This is like when gnar goes mega and dives the enemy team. That's not to say that Kog'maw directly engages fights. He used to turn into THE spellweaving ADC hypercarry. It's all about how Kog'Maw's team has to adapt playstyles around him just like a team with a gnar.
The problem is that in order to do this, AD Kog's poke/mage state needs to actually be able to poke. His E has to deal damage. His ULT has to actually do damage. His W needs to feel like a state change, in that it should not be limited by mana.
I love AP kog'maw. I adore it. But now you're beating a dead horse. You've killed it. I think it's time to make it official if it means you can actually fix AD. Get rid of his AP ratios and revert his ult to actually doing some poke damage for AD Kog so that he can go back to being a unique ADC with an amazing playstyle.
No other ADC had state changes. No other ADC was a spell weaving late game hypercarry. He's way more interesting and way more fun with the adaptive play pattern. If you balance him around his autos alone he's just going to feel like another Jinx.