Another thread about Vayne needing a nerf
Today I found out through a LoL wiki that Vayne's bonus damage from her tumble can crit without any reduction. I tested this in a custom game just a few minutes ago. My autos were dealing 82(Butcher mastery adding +5) damage to minions, my tumble auto was dealing 120, so tumble is adding about 38 damage, my regular crit was 160* and my tumble crit was hitting 236 pre IE. 77x2 = 154 + 38 from tumble is only 192, but add another instance of tumble's damage and 230 + 5 from butcher, and I guess natural talent gave me a decimal on my AD that made it round up to 236. Farmed up IE, did the same test, and the crit modifier applies. This means that a tumble auto from vayne that crits deals 250% + 175% AD for a total of 425% AD, and it can happen every two seconds without any CDR when Q is maxed. Ever been playing AD carry and had a Vayne suddenly pop out of invis and almost one shot you when she's on-par or behind? Well that's why.
In addition to that, the preseason changes gave her a pretty big buff, and gave her more reaction time against most of the popular assassins that would've been able to deal with her. With the stealth changes Vayne's invis is nearly uncounterable, with only champions with true sight granting abilities such as Lee Sin and Caitlyn being able to really fight against it. The Fervor of Battle changes also worked out in her favor since the flat AD gained from it now interacts with the crit she naturally accrues through her affinity for attack speed, and spills over into her tumble crit amp.
She's been infamous since forever because of silver bolts making her great for killing tanks, and for being a really strong duelist among ADCs, but now with the buffs she's gotten recently and her Q's ability to crit she bursts really hard in addition to having ADC dps, tank shred, and being much more slippery than most other ADCs; her only real weakness is her laning phase and burst, the latter got weakened in the assassin update and the former isn't really a weakness since she tends to outscale most other ADCs even if she loses lane. Her average win rate on champion.gg is 53.19% with an average pick rate of 25.7%, while most AD carries hold around a 50% win rate with a much lower pick rate, so she's definitely above average; the only other AD carry that matches up is Caitlyn with a 27.64% average play rate and a 52% win rate, which is understandable due to green father's blessing, fresh blood and her naturally high AA range, and also because she's Vayne's biggest counter.
*The discrepancy between this crit number and my regular damage is due to the butcher mastery not being able to crit, and because of a decimal rounding up from the natural talent passive