Gangplank is doing EXACTLY what old Nidalee was doing but far worse
Sitting in lane farming safely with basically no way to stop it (without a gank or 100-0'ing) then landing one spear (or barrel in GP's case) then suddenly your opponent has no HP and has to go b or die from the next hit. Not to mention ever since everyone started copying the barrel thing it's been more and more infuriating trying to dodge them, considering he can throw them a galaxy away and gets a massively retarded speed boost + slow on them when they connect.
It's not fun to play against someone sitting at their tower clearing waves then just so happens to land ONE ability from a distance not many champs can trade from and suddenly he gets ahead.
"just destroy the barrels' I'll give that some leniency on ranged champs but melee champs have barely any chance to react before he blows one up from a bush. It's a lot easier early game with the slow ticker to do than it is late game where by time you reach the barrel he's already about to explode it
Nidalee was doing the EXACT same thing as Gangplank is doing now and he's not being nerfed meanwhile Nidalee got an entire rework because of how unhealthy ONE ability was, the rest of her kit was fine.
If i must step in...
Friend, in as a connoisseur of morse- er, top lane champions. I must say that gangplank has some good laning early. Remember more importantly though. It's about you getting your meal- gold i mean...
