So, what's Vayne current state ?
That's not a QQ at all. Really, I see
pratically everygame. She can be really oppressive in lane if her support picked well. By the way, she has mobility, a potential stun which can be outrageous in an 1v1 situation. She has awful damages lategame. Yeah, this is adcs' purpose, but Vayne's are too much.
No need to say she's pretty damn early, because in a 2v2, Vayne can easily use her true damage, which gives her big advantages.
I don't think she's super-hard to play. First game I played her, I got fed easily, and I didn't find this hard.
To finish, I wanna specify that I never play adc (don't want to play against Vayne every game, actually) but I still have problems with her when I play jungle, for example. Even if I focus botlane with strong early junglers, she will destroy my team in lategame, no matter what we do. And I found this really annoying.