Thorn has crazy power but as others said, she is difficult to handle. For one, your aim has to be really good to be anywhere decent with her, her bow draw takes a bit long which I’m sure not everyone can get used to, she can’t stand in one spot like a sniper for too long, and needs to be constantly moving which is why she has such high mobility. That being said her run jump and shoot combined with her bow draw makes things a bit difficult while trying to use her if you have ■■■■■■ aiming skills.
I really consider rath as the most op because he’s so “pick up and play” that anyone can get their best game out of him.