Riot, are you serious with those PBE Gangplank nerfs!?
I really feel like you are very disconnected from the actual game... After all the nerfs you have delivered already, he is honestly quite balanced. His early game is completely non-existant. Anyone can completely annihilate him before he gets at least a Trinity Force. He is SO easy to shut down. All he has is his good late game scaling, which you can easily delay by beating him early. All of his kit's power is in the one or two barrel combos he can land in a teamfight.
I don't understand why you always seem to pick a champion and make them useless patch after patch, all of that while ignoring a lot of much worse offenders. Gangplank can be very strong if he's fed, but honestly he has plenty of counterplay. Granted, if you give him 5 kills for free he's going to stomp, but so are most other champions. I mean, all ADCs are MUCH stronger than they used to be. I don't see the difference, except GP is much higher skill cap than most champions and requires you to be on-point with your timing and combos. And that will reward you with strong damage, as well as it should.
What about other champions that can one shot you easily without even requiring that level of mastery? What about all the LeBlanc, Riven, Annie, Tryndamere...? Champions that literally have inherently broken kits? Champions that will beat you at any point in the game very easily simply by clicking on you? What about those? Are those just ok to stay there for years, being that strong and annoying and yet simple to use?
You are doing the Kha'Zix thing all over again Riot. You really are. And we all know how well that turned out. I really hope you reconsider your nerfing spree on Gangplank, because at the moment he is a healthy high skill - high reward champion that is nowhere near needing to be gutted this way.