Game Breaker : the Formless Imperial Sword Technique at the beginning at least
Sculpting as it turns out
The dexterity stat
Firstly, the Formless Imperial Sword Technique is not the best sword technique around, Weed just get it early on and use it effectively.Secondly, the sculptor is a craftman class so its combat power is pathetic, Weed is only luck out with his special subclass and it require much more effort to advance than combat classes.Thirdly, while Dexterity is one of the best way to increase attack power for craftman classes, combat classes also get a lot of attack power boosts so it is not that special.
Dreadful Musician : Weed has several times shown that his singing (he also writes his own lyrics) will make enemies of all his listeners, no matter how much sweet talking he has done. When posting one of his battles on the internet while transformed into an orc people think it is a parody of how the orcs have no culture. He is completely unaware of how bad he is.