Gangplank needs to choose
Either he's a late game super pick and actually needs to work to get there, or he's an early game snowballer that has unique ways to rack up gold.
TF has his passives and his ult to rack up gold, but he's not a late game monster. Draven has his passive, but he also falls off. Why does GP have his global ult for kill snatching, his passives to gain gold, AND he's strong late game? Maybe that's the real problem with Gangplank?