User blog comment:Freedfg/Is vayne TOO versatile?/@comment-3486816-20130725212020

Probably already been mentioned, but it's worth noting that all the other 550 range carries you mention have longer-ranged skills than vayne does. Any time you try to land a skillshot on Ezreal or Corki you risk their own retaliation, and if you try to hit them with Vayne, they'll have plenty of time to hit you with their long-range skills before you even get in range. Vayne's skills require really risky positioning to use offensively.

Honestly if you're having trouble with Vayne, blame whoever took exhaust on your team. Anything she does basically puts her within range of it, and when she ults it makes her all the more noticeable when she exits stealth so that you can immediately shift focus back to her even if you don't have oracle's.