Being real with ya, it isn't as good as it used to be. The main appeal of it used to be that you could just sit in lane and spam oranges to keep your health up. But since oranges a massive boost from being low life, instead of scaling well with levels like they used to, it can't be used to top up your health unless you're rather low. Also Lich Bane's scaling got nerfed since this guides creation. If that was undone by giving gp's Q a .2 ap scaling, then this'd be completely fine. But as is, competitively, this guide's a bit of a relic.

If you're trying to learn gangplank in a serious manner I recommend you pick up one of the critplank style builds instead. While ap gp is cool and can be very fun, it's mostly just taking advantage of a weird stat scaling he was given ages ago. Because of that it tends to be ignored by the riot balance team, which ultimately makes it weaker than his primary crit builds which get the attention.

That said I'm glad you enjoyed my guide and maybe got something out of it. Your comment actually got me to update some of the stuff in it that I've putting off for a while now.

Yeah GP can get out of any CC's other than Knockups, including silences. Funnily Yasuo's ult and Nami's bubble count as Suppresions, meaning those can be orange'd out of as well despite looking like knockups (though you have to have mad timing for it to work on the yas ult).

In terms of item build, it's old, outdated at this stage (I mean it still has Crystalline flask in it XD ). I got really put off GP after the rework for a while since his Oranges aren't as great for sustain on ap gp anymore, since you need to be pretty low to break even on the old heal now (for ap gp, for regular gp it was a straight buff pretty much). But anyways, the main reason the build's sub optimal atm is because there's now a load more CDR floating around on items now (such as the mentioned abyssal scepter) that wasn't when I wrote this up, as well as new items brought into the game and old ones having their functionality changed. I've made some adjustments to the cheatsheet to be a little more inline with one should be building nowadays. You're right about abyssal being generally better than spirit visage, but visage is still a good pure defense item for mr, so I've moved it to being a secondary option instead of removing it entirely.

Dead man's plate's a solid pickup, though I'd be more inclined to go for a zhonya's in general. On the other hand Dead Man's plate synergizes with magic penetration thanks to it's passive so there could be something there.

In terms of other items I'd mess with, the new hextech revolver is a pretty sweet item since it goes so well with AP GP's Q, and protobelt isn't a waste since gp lacks mobility aside from barrels. But that's just speculation. Chances are the revolver is good, but not worth upgrading into protobelt, and thus not worth keeping for late game.

Runeglaive was removed, it got replaced with runic echoes which operates very differently for GP specifically since it has no on hit/crit interaction that runeglaive had. The only reason I keep that build there is as a reminder of the only time in leagues history that AP GP was incredibly strong compared to most meta champions.

Sorry I didn't respond right away btw. I like to think I'm pretty quick with my responses on most of my guides but I was pretty busy this weekend so i never got around to looking over my stuff.

Anyways I'll be editing this guide for the next couple days to bring it up to date, clearly I've put it off for too long, so if you've got anymore comments I'll be around :)