The Gangplank nerfs are just a kick to the balls
Riot not only nerfed Gangplank unnecessarily hard, they also nerfed him in the wrong way; they forced him to be less aggressive and interactive in lane, instead of just embracing that aggression and tuning it. I've always hated the Tobias Fate play style of sit in lane and farm and do nothing, just wait for mid game.
But if riot wants that passive playstyle for GP in lane, then at least make the barrels scale to a 60 second duration. Gangplank's late game is already weak as fuck, now it's even weaker, with less barrels + no vision on said barrels (the vision nerf is huge). Everyone thinks GP has a great late game, but no, he only seems that way cause he gets to that late game before you do (check the stats if you don't believe me).
Gangplank only gained power through kleptomancy (A horrid rune I wish never existed), bandit on support items (supports didn't need the extra income), and the non-existance of bruisers. Klepto was nerfed, bandit is being removed, bruisers are being buffed, and getting a nice new keystone.
I've been unhappy with the balance team for a while (since the ardent charade started), and I've been hopeful every patch since then, but everyone has limits, so I'll be quitting league for a while (a month or two) in hopes of returning to an actual balanced game.
Finally, I'll leave you with neace: