Green Arrow in my opinion is one of the best if not the best marksman in the game he is an amazing lane bully and he also scales extreamly well into the later game. The reason for his amazing lanning phase is his W,R combo together they can take the oposing marksman or whoever even a tanky champion to half health. The reason for his amazing scaling is his W gives passive armor pen so when u start to get more armor pen from your items as well as the W passive u will melt entire teams.