I think he needs a damage rework.
After rework his Q scaled really hard, making his barrels OP.
Now his Q is weak, with his barrels doing okay damage.
I think Gangplank would be in a better spot if we just separate the two skills without having them both scale off of each other.
That or less barrel cooldown (less gold given when enemies destroy it) to allow him to actually siege in team fights.
Where as right now I land a sick triple barrel set up after practicing it alot- only to have the enemy team be extra careful or tanks just walk through them like nothing.