The problem with the "Tank Buster" myth about Vayne, is that silver bolts true damage is JUST as effective against squishy targets; yes the numbers are lower, but its the same % as tanks.
Combine that with the same bullshit assassin design as champs like Ahri and Malz where they hit you with CC then rip most of your health off while you cant fight back meaning you can only run away and they have kits to make running away hard... shes too good vs too much. She gets ahead, no way to stop her, shes just ahead now... I mean you cant send a tank in to lock her down while an ADC gets her, shes slippery and may even kill the ADC then kite the tank to death.
Shes in that weird place like LeBlanc where the numbers have to be sub optimal or they are out of control (season 5 Vayne in every game), but still playable. As for 1300 crits, 1k crits are bad enough, but she can go over 1k. I think this is a problem because its such a painful initiation that most ADCs cant inflict enough back to win a fight. Too much front loaded burst. It wouldnt be as bad if she didnt also have her E to potentially auto win fights.
Vayne is probably not going to ever see any sort of proper fine tuning, just going to be kept functional but not META like LeBlanc, Urgot, and other champs that have problems.