The most difficult? As opposed to Ekko who needs to set up his field where you're going to be in five seconds? Or Veigar who has to hit you on the edge of a delayed cage that anyone with a dash can get out of when they see it coming or even just walk out of range?
It's a chain that gives an assassin a slow and a snare for both chase and disengage if necessary and the discussion is on what to do to balance it if they make it faster so your point about it being slow isn't really valid in this case and as a skill shot it has a wide hit box.
Personally I don't mind LeBlanc, even laning against her as a squishy mage, but you're really trying to make it sound like she's more mechanically difficult than she is.