Guess what the Kog'Maw revert without restoring Living Artillery will do...
Here's how they nerfed the hell out of this ability when they wanted to put a whole champion's kit into his W:
R - Living Artillery COST 40 mana ⇒ 50 mana DAMAGE 80/120/160 ⇒ 70/110/150 ABILITY POWER RATIO 0.3 ⇒ 0.25 BONUS ATTACK DAMAGE RATIO 0.5 ⇒ 0.65 VISION DURATION 4 seconds ⇒ 2 seconds MANA DEBUFF DURATION 6 seconds ⇒ 10 seconds REMOVEDDON'T TOUCH THAT No longer deals 100% increased base damage to champions NEWSMELLS LIKE FEAR Now deals double damage to enemies between 25% and 50% health NEWSMELLS LIKE DESPERATION Now deals triple to enemies between 0% and 25% health
Now that they realized having a champion that stands in one place and right clicks to either melt you or die isn't the healthiest kit, they want to restore his kit to the old state, but leave this mess of an ult as it is.
Here's what's going to happen: If they restore his W and Q to the exact values they were before the rework, he's going to be the lowest winrate marksman in the game and borderline unplayable, because his ult will be an objectively much weaker ability than his old one. Then they'll have to buff him somehow, and as they seem to hate the idea of an artillery marksman, they will probably put more damage into his W/more attack speed into his Q. The result is the same stat-checky one-dimensional basic attack champion we have now except he'll be able to attack move.
Because that's a fun champion design guys. An ADC that only does things all the other marksmens can do as well, except he scales better with items. God forbid we get a fun to play artillery ADC, it would be way too hard to just remove the AP scalings on his old ult or add an ammo system to make it easier to balance.