Why does Leblanc even have a root?

Double displacement high burst champ with a stealth passive, and then you give this champ a root so that she can pretty much peel off any retaliation from melee champs with a huge ass radius chain that also serves as one of the best assassin chase down tools? Landing her chain is almost impossible to miss given its animation time and how it's comboed in point blank range to begin with, and breaking it has even less counterplay.

It should be a slow, not a damn root.

Zoe got nerfed because of low cd poke and crazy mobility, yet she always relied on landing a much slower and telegraphed sleepy bubble to do her burst while Leblanc's combo is pretty much impossible to fail unless facing something with hard CC like an Ahri or Lissandra.

I'm trying to understand how some assassins (not Zed or Katarina, but low mobility assassins like Talon, Fizz, etc) or low mobility mages are going to cope with this ever increasing amount of high mobility high burst poke champs.

It's pretty annoying to face against champs with lethals damage that have pretty narrow windows of retaliation compared to more traditional champs with less mobility.