Is it an unfair advantage for other players if some players use longer of more bendy stick?
There's no stick that's objectively better than others. Different flexes and lengths have their advantages and disadvantages, and in the end it's up to the player to be comfortable with his stick.
Yes I think this has been a huge problem. How come Chara has to use such a large stick while Marner uses a smaller one.
#stopstickdiscrimination