I get what barrels do and how you're supposed to use them. And my point is, what does any of that even matter if it's trivial to simply stay out of its range and then kill it at your leisure? The barrels have very unimpressive range and die to one auto attack. Ranged champions in particular can pretty much pretend like Gangplank doesn't even have an E.
Melee champions have the potential to get zoned by the barrels, but even then there is plenty of counterplay. Because GP has to use his Q to farm to get silver serpents, he's much less tempted to save it to detonate barrels. A melee champ can simply wait for him to detonate the barrel or last hit a minion for farm, then destroy any remaining barrels while his Q is off CD.
The problem is that the ability has so much counterplay that it's entirely dependent on your enemy fucking up. This is the same problem people have with Veigar's reworked E, so why am I not seeing any complaints about this one?