Leblanc needs to require skill.
She doesn't. She has a 100% sure kill on the enemy mid laner, with little risk to herself. Her base damage and scaling are too high, and for someone who doesn't put themselves at any risk to kill a player, because she teleports in and instantly kills them after taking away half their hp with just 1 of her silence balls.
In lane all she has to do is stand there to zone the other laner, and if he steps out, she gets to take away a huge portion of their HP with no consequence to herself.