being meta and being a broken cancer champion are two different things. They are not mutually exclusive, nor are they dependent on one another. Win rate and play rate say nothing about a champion's design health or enjoy-ability to play against/with.
Vayne is now, will always be (unless they change her kit), and has always been an absolute tumor.
A champion should not have all of these things in one kit:
-Invisibility
-Self peel
-Hard crowd control
-Auto attack reset
-Auto attack steroid
-Movement speed steroid
-% health true damage (a stat that should be completely eliminated from the game entirely)
-Ultimate resets
-The ability to build bruiser/tank and still do ridiculous damage (top lane mallet/deaths dance/steraks/BT/etc.)
Does this make her ovepowered? No. Well... currently yes... but we've seen her shift in and out of the meta. So "overpowered" isn't appropriate, except for right now in the current patch cycle.
But overall, she is and always has been an overloaded, oppressive, cancerous champion to play against.
How many games have you played where your win condition was "Kill vayne"
How many of those games have you lost?