The biggest issue that a lot players take grievance with regarding LeBlanc is her tether range. It's way too long (out-ranging Caitlyn's ultimate) and has a generous hitbox to boot. A semi-competent Leblanc will dash in, throw Chains, throw Q, and then follow up with an auto-attack if they didn't damage their target with Distortion.
There was very little, if any, counterplay to that. It was a major factor that led to her rework. However, people complained and she got reverted. Making matters even more irksome, Runes Reforged allowed her even greater kill potential via the Domination Tree.
It gives her all of the stats and utility she wishes she had at the beginning of a match, meaning she no longer has to worry about buying the items she needed to acquire before Runes Reforged.
IMO, Riot just needs to add a mechanic to her Chains, where the range of the tether is directly proportional to how far the Chains travel before hitting a target. Should she throw down a pointblank Chain, she will have to commit to an attack.
As things are now, LeBlanc holds too much initiative.