I think the issue with Vayne can be very easily fixable.

The problem is she goes 0-3, 0-2 or whatever score that leaves her behind, she will solo farm a lane and the rest rotate. By doing this she will actually outlevel the fed enemy adc and she hits her power spike with a stattik shiv, when she presses R she gains 40 ad which is a free b.f sword, then with her W giving her free True damage she literally will either out damage you or even damage at worst.

Im basically saying shes given so much free stats for absolutely no reason. She doesnt need a free b.f sword when she presses R, she gains invisiblity and her passive is increased ( movement speed ), Why not work around her Ult and change that free b.f into something else?

Ive never seen a champ so lost and weird, shes just a clunk of free stats.

I was thinking something along these lines

Old Why was this even here Vayne no longer gains AD after ultimate cast.

New Cant touch this Vayne gains .3 seconds of duration for every successful tumble hit in ultimate form ( NOT PERMANENT ) so it resets everytime she R's and awards her for actually hitting something instead of just giving her a free b.f sword

Or if thats not something you want just remove her free AD

and give her free ad based on every time she autos in Ultimate form after tumble UP to that new amount,

I just want her to not press R and get a free b.f sword, thats all. What do you guys think