LeBlanc just picked up a triple kill at bottom. She can 100 to 0 my Vel'koz without landing anything

1-1-0 Vel'koz, 1-1-0 LeBlanc. I traded kills with LeBlanc at level 4. I almost kill her again at level 5 because she's pretty bad, but her jungle comes and saves her. We both recall.

At bottom lane, my bottom and jungle dive between the two turrets and get a double kill. Enemy jungle comes to defend, I spam ping for them to retreat, and type out 'LB coming.' They get greedy, dive the jungle, kill him, and then LeBlanc cleans them up for a triple kill.

LeBlanc is now 4-1-0. She returns directly to lane without buying and I kill her, because she can't avoid skill shots. At all.

And then she returns to lane with Gunblade and 100 to 0's me without landing her E or W. She dashes into me and misses, I hit her with Q mid-dash, E + W her as she lands, kite her around the minion wave for a second and she whiffs chains, and then I ult, thinking that I can safely kill her, as I have 80% of my health and she's missed all of her abilities.

Nope. She hits me with Gunblade + Ignite + procs passive with a mimic'd Q and I go from 80% to dead.

I'm really not sure how this is healthy. Even building MR against this, I still would have died had she landed either her E or W. Champions should not be able to effectively kill another champion with limited counterplay after having missed their entire kit.