this is going to be a medium-length rant post about youalreadyreadthetitleI'mnotgoingtosayitagain.
Please consider that this is all personal opinion and is in no way based on any professional knowledge.
So first of all, let it be known that I LOVE what they did visually. His splash art is probably one of the most impresssive ones ever. It just tells you so much about his character without even reading the lore. You look at this and you know he is the Pirate King. He is not one to be messed with.
However, unfortunately enough, Visuals don't make up for bad gameplay and here's the problem:
The old Gp could generally be described as: a weird bruiser/marksman with a single valuable ability and a few other mildly useful gimmicks that were not connected in any way. His only way of being actually useful was to build Crit and on-hit efffects and use it with that one defining ability.
He was no duelist, no real splitpusher,..the closest thing he could be considered is a one-spell assassin...or a global support.
With the rework, Riot essentially changed NOTHING with the problems that old GP had.
What they did, was trying to keep and emphasize all the aspects that were the reason he was up for a rework in the first place. The problem is not so much that they tried to preserve some of his gameplay...the problem is that they preserved EVERYTHING.
His Q is basically the same, but they decided to focus even more on the farming aspect by giving him a second currency used for upgrading his ult.
So basically, the one really boring part in gangplank's kit...the early game, where you couldn't do jackshit with your Q because it had no damage, and cost way too much mana to spamharass effectively...is still the same. You still have to run around and Q minions from afar and hope that you're up against an enemy who can't justwalk right at you and shit in your face.
Now here is where the passive SHOULD come in.
Previously, his passive was basically the game's worst DoT and slow in the whole game, just thrown into his kit because they had no other ideas.
Now his passive is just a different shitty DoT.
the idea was probably to ive him more presence in lane, because his kit has no real way of fighting an enemy pre-6 and pre damage items. This isn't even a bad idea, except you'd have to walk up to your enemy and whack them which is not what you want, since you should focus on shooting minions for gold. It's pretty much just a defensive mindgame that prevents your opponent from jsut recklessly attacking you because you have no damage anyways.
Moreover, this passive is useless in relation to his kit and his playstyle. GP still wants to be a damage-dealing skirmisher who stays on the outside of fights an shoots people for massive crit damage. Even after the changes he's still not a straight up duelist....He just lacks the DPS for that.
Here's where the problems continue....so after NOT making him an actual fighter, therefore still making him reliant on Q and crits, Riot (unnecessarily imo) adds another, slightly more confusing mechanic...the barrels.
basically it's supposed to be a way to do AoE crits, as well as huge minion wave farming with Q...and that wouldn't be such a bad thing if the barrels weren't super awkward to use.
They take way too long to "arm" (get to the point where you can shoot them), the barrel chain reactions are happening so slowly that you can't do with them what you want to do (activating them from afar in a tricky fashion, rather than just stacking the around you and hoping someone will be dumb enough to walk into them)....heck, thanks to his passive, even wavefarming is a pain in the ass, because what you'd want to do is get all minions low enough for one barrel to kill them, but with that passive burn and general the fact tat you want to stay out of melee range most of the time, it get really hard to control the minion wave.
To sum that one up: They took some power from Q and gave it to E which makes his job a lot harder at times.
Finally, the one thing that bugs me the most:
Remove Scurvy is probably one of the most broken abilities in the game. It's basically a free Quicksilver + heal. I could name you a few champions that would be out of control if they had this ability instead of another one of theirs ( Vayne, Cassiopeia, Kayle)
What do these champs have in common? they are DPS champs. Gangplank. IS NOT. a DPS champ.
GP does burst. He's a hit'n'run one-hit wonder (in the most literal sense possible). The only justification for this ability is that it helps him when he's getting hit by CC, while he's running in and out, so he won't get caught. Other than that this ability has no real benefit to him other than being a nostalgic trademark. There's no other reason that this ability remained other than being a huge meme.
There are so many things Riot could have done if they focused more on rebuilding him as something unique (barrel based kit, more in-kit interaction, possibly with ult detonating barrels instantly or something), yet they insisted on keeping his awkward, unreliable nature as a crit-caster with a citrus fetish.
The one thing that's an improvement is the ult upgrades...however, I think the Silver serpent cost is way too high. It takes quite long to reach 500 SS, even if you are "winning" your lane (that means not getting pooped on and farming like you're cosplaying Nasus)
So overall, I WANt to like him, but atm I consider him unreliable, unviable, and generally a disappointment in terms of gameplay improvement.
But maybe I'm wrong. Maybe we just need to wait and somebody finds a super strong build that works in all phases of the game and makes him and overall good champion...but until then, I remain sad.