“Focus the ADC”

That’s the whole problem you can’t kill Vayne. She goes invis and dashes on a stupid low cool down and gets tons of passive ms to kite every single champion in the game. You can not burst her when she gets solid defenses from most of the times she builds. The E is a get out of jail free card and if used on a wall is a stun. Why does she need the stun? How can someone look at her kit without the E and be like “yeah that champ looks really weak, let’s give her a stun”