It's the perfect time to buff Vayne
I think it's universally agreed that Vayne is in a bad spot right now, ever since the itemization changes making IE a top tier item when it doesn't work so well on Vayne.
With the overflow of tanks last patch brought, I can't be the only one having trouble dealing with pure tanks (be honest, when was the last time didn't see a Sion/Naut/Sejuani either picked or banned). Vayne is the ultimate tank killer, no other champion does it as well as she does, but she isn't viable, I think buffing her is a rational direction to prevent tanks from getting out of control.
is ultimate tank killer. 600 ap means up to 51% max health damage, if my math is right. But normal Varus is pretty good at it too.