Analyzing LeBlanc's combos, and how she could be changed (nerfed) to make her balanced and healthy

We all know LeBlanc as the bursty, hypermobile turboslut that terrorizes the mid lane. With one of her few natural lane counters, Kassadin, having been nerfed, she's now shining even brighter in the spotlight. To me, the biggest problem about LeBlanc isn't the fact that she has burst, or that she has mobility, but that those things combine to give her huge burst poke (with little to no counterplay).

LeBlanc's biggest burst combo is her QRWE, which at max rank does a total 1435 base damage + 370% AP... but this combo really isn't a huge problem to me. She either has to flash on an unsuspecting victim, or catch somebody from fog of war with it; to land the full combo is an outplay. The combos that (to me) are problematic are the long range burst poke combos, for example, she uses W to get in range for Q + R + E. If she lands the chain, that's a whopping 1050 + 260% AP from 1300 range in less than a second.

My proposed change is to make LeBlanc's Q and Mimic Q unable to trigger the mark on each other. She would HAVE to trigger the mark with her Distortion or Ethereal Chains. This would make the Q + R combo (a point and click combo requiring no skill to execute) MUCH less potent, and would force her to use Distortion or land the Ethereal Chains to burst down opponents.