What were they smoking when they designed Dark Harvest?
An infinitely-scaling Sheen-like that scales on AP, AD and number of units killed. Aka. you kill more units to get better at killing champions, making snowballing even worse. My last game, whatever was to be said about Orianna going 0/6, had an Ezreal midlane with Dark Harvest. At Lv8, when ahead 3-5 kills, guess how much his Q did to me after he bought Shiv (another broken item which stacks so well with Dark Harvest, thanks Riot) and a few Lethality items? 20%? 30%? 50%? Try 87% of my health... with one Q on a 3s CD.
Why? Any champions that abuse it 
are labeled problematic... so uh... why make them even worse?