Let's talk Gangplank

Ahh , everyone's favorite (or least favorite) pirate. Terror of the high seas and the top lane, he has been popping up recently ever since his mini-rework. When his morale boost was replaced by chains of exploding barrels, he's been a terror of the late game, destroying tanks and squishies alike with massive armor penetration. But was this the goal? With the changes on the PBE, where the 40% armor pen it has on live being changed to 60% bonus pen, what is the purpose of the barrels? Are they supposed to allow a melee AD carry hurt tanks? But he has true damage on autos and a massive magic AoE DoT. He has the mixed damage to help him take down armor stackers, so why the change?

I always saw the percent penetration, combined with the bonus flat damage, is what made those barrels something to be scared of for all champions, whether they had 50 armor or 500 armor. If Gangplank hit that chain, and you were in range, you were going to get hurt. Badly. Changing the pen from total to bonus simply makes it less effective against squishies, with ad carries or mages being some of the best to destroy his barrels with their long range.

Mainly what I want to know is what you all think of GP. What is his role? What is the purpose of his barrels? Is he an anti-carry like Jax or Rengar? A split pusher like Yi or Nasus? Or a late game team fight god? I always saw him as a team fighter, someone that everyone needs to fear and respect, but some of the changes make me think differently. What's your thoughts on the pirate king?

(Just an FYI. I'm part of the silver scrub club, so I probably don't know much balance wise.)