Vayne is already an incredibly strong counter to tanky champions. This makes her an even harder counter but it doesn't make her attractive in the other scenarios. I don't like the idea of Vayne being just a free win into tanky compositions. I thought Riot was trying to discourage rock-paper-scissors type gameplay.
BTW: I think the Twitch buffs are quite scary. He might just become a free win late game too and with the BoRK cost decrease + IE buff + anti-snowballing changes, he might get there more often. In general, I think the hotfix, system changes, plus the planned ADC buffs will pretty much revert this more diverse meta.