My thoughts on Vayne:

She's probably getting nerfs but honestly even if they nerf her Q she will still probably be a little on the strong side.

She's never had real invisibility. For a long time if Vayne got fed you could at least buy an oracles or a pink ward if you absolutely had to deny her, so she was given some power to make up for that. Right now you can't do that, and that extra power she's had all along is still there.

The fact that her Q can crit now is pushing her way over the edge, but even after removing that, she will still be a little too strong because she has less counterplay than she used to have. I'm not saying pink ward to stop vayne ought to be valid counterplay (it makes vayne players feel like shit), I'm just saying she has always had a bit of extra power to make up for that and now she doesn't need it.

Right now she does so much damage in such few attacks she can kill someone in the span of going invisible by tumbling once or perhaps twice. I'd rather she go invisible 3 or 4 times per kill but extend the duration of her ult so she can do that throughout the entire team fight.

If it were up to me I'd extend the duration of her ult by about 4 extra seconds per kill or assist and completely remove the bonus attack damage it grants, and make it so that during her ultimate she can tumble while CC'd (still can't do other actions if they are prevented by the CC, like attack or cast other spells or move or etc).

Vayne's identity is Tactical Stealth. Its not bonkers damage in 2 or 3 attacks. I realize a lot of vayne players might disagree, and they don't want vayne to lose alot of damage. But there isn't a lot of room here. She's either going to lose some damage or lose some of the power of her stealth.

We already have marksmen that do silly damage in few attacks, for instance draven. Vayne isn't really supposed to be that, she's just had to be that to exist as a champion because real invisibility was never a thing until now.

Vayne is supposed to be a shadow at the corner of your eye that puts a bolt in your skull, and every time you turn to see what did it all you see is a puff of smoke. She's not supposed to be someone who comes out of stealth and blows you up in one second-- eve, rengar, twitch and khazix have received multiple reworks to keep them from doing exactly that.