Is jungler as a role overpowered?
Let's first think about a team fight. It's hard to tell which team is going to win if it's a 5 vs 5 fight. You can still possibly win if it's 4 vs 5, but you can hardly when it's 3 vs 5. 5 over 5 is 1; 5 over 4 is 1.25; 4 over 3 is 1.33; 5 over 3 is 1.67. You can tell that the higher the ratio of your team size over the enemy team size the more likely you are going to win a fight. Let's not forget how much effort you need to kill two members of the enemy team to reach the ratio of 1.67! However, a very common early game gank can give the enemy team an incredibly high ratio of 2 (2 over 1). With a jungler simply walking by and landing some cheap damage, the enemy gets gold advantage way too easy. I understand the role of a jungler, but early game gank should not be so easy for the enemy jungler with or without your jungler around.