Kog'Maw Buff Suggestion
I suggest this due to Kog'Maw's lack of mobility, and his "shining moment" being the few seconds his Bio-Arcane Barrage is active. This would give him a better chase ability, a form of easily counterplayed disengage, and a better tool for following up a skirmish with last-ditch Living Artillery usages to try and finish off a runner.
Void Ooze
Cost: 80/90/100/110/120 Mana Range: 1200
Kog'Maw launches a peculiar ooze which damages all enemies it passes through and leaves a trail which slows enemies who stand on it. Deals 60/110/160/210/260 (+70% Ability Power) magic damage to enemies it passes through and leaves a trail which slows enemies by 20/28/36/44/52% for 4 seconds. Kog'Maw gains 15/20/25/30/35 bonus movement speed while moving on the trail left by Void Ooze.
I'd imagine maybe a reduction to the actual slow percentages would be in order, but I think a change like this, or something similar, would be good for Kog'Maw because it would give him a form of repositioning/chase tool. It also opens up the gameplay choice "Do I save Void Ooze to escape, or use it to slow my target."
I'm not sure what would be more appropriate: a flat movespeed bonus, or percentage. I was thinking flat might be easier to balance and tweak, but I'm no game designer, so I'm not sure.
Just a thought I had to give the little guy a chance to have some more mobility in teamfights and skirmishes. Please let me know if it's feasible or just a terrible idea all around. I figured with his low movespeed, durability, and short range unless Bio-Arcane Barrage is active, he could use a little love-tap.