Nerf Vayne by adding trading windows against her

Since Vayne's early trading is actually not bad at all especially when she's allowed a cutlass, what if we added a window to her W? Rather than it being another passive, what if it was an activatable steroid that costed mana? Like if it drained mana and was toggled OR make it an activated steroid

This would allow more windows for her to be dominated in the early game, like she's supposed to be