Assassin/Mobility Counter-play

I'm sure I'm not the only one that feels like LeBlanc, Yasuo, and Zed are extremely un-fun champions to play against, most of that frustration, at least for me, is due to the fact that out-playing them is much more difficult than it is to be out-played by them. I think we should introduce a mobility counter mechanic, for Yasuo (and maybe Lucian), I think slows should reduce the frequency that they can dash, or alternatively, the distance that they dash. For Zed/LeBlanc, I think the time that they have to teleport back to their shadow/w should be reduced by either slows or exhaust.