Jungle Vayne?
With the new patch, I decided to see if Jungle Vayne was really strong with the new Sated Devourer. In a custom game, I jungled Vayne, and I also have a custom game where I went normal ADC Vayne in lane. I wanted to see if the amount of true damage dealt by a Sated Devourer Vayne was significantly higher than that of an ADC Vayne.
Full Jungle Vayne Build:
Full ADC Vayne Build:

So, with these builds, I had a game (I know that an ADC usually builds a defensive item) in a controlled environment. After, I compared the damage dealt to champions (because that's what matters in a fight).
Jungle Vayne Physical Damage %: 71.55% Magic Damage %: 13.43% True Damage %: 15.19%
ADC Vayne Physical Damage %: 88.00% Magic Damage %: Negligible True Damage %: 12.00%
So, Sated Devourer Jungle Vayne deals 20% more true damage than an ADC Vayne with the given builds. And while Jungle Vayne can proc Silver Bolts really quickly, and with a
to add extra true damage, she only deals 20% extra true damage to champions than an ADC (mind you in a custom game, so statistics may be a bit off from in an actual game). The Devourer jungle item actually contributes heavily to her magic damage, which, ADC Vayne has nearly none of (the actual percentage for magic damage on my ADC Vayne was about .001% and I don't know where that came from).
Does this mean that Jungle Vayne may become a thing? I think not. She has to deal with a lot of problems in the jungle, namely a lack of sustain (she could actually clear it quickly with a normal
(non-sated),
, and
with little damage). I found myself chugging 2-3
per camp in the early game.
So, in the end, while a Sated Devourer Vayne deals more true damage than an ADC Vayne, it is 20% more true damage (I thought that it'd be closer to 50% extra true damage). I doubt that Jungle Vayne will emerge at the next big thing. While Vayne is capable of shredding tanks and stuff (against some tanks, she can deal nearly 50% true damage to them), being a Sated Devourer Vayne isn't going to make you a true damage god (with mixed feelings). Of course, it'd take a lot more matches (in actual games) to figure out more accurate statistics, but I did my best with a match of each.
If you want to, try it out. Vayne had to deal with a lot of early game problems, but her Tumble got her AA resets which helped a ton in clearing camps. Her Silver Bolts just added on damage, and her Condemn helped with keeping damage down by stunning the camp monsters. But once she got rolling, she could clear easily.
Just wanted you to know.
. You can counterjungle quickly, stack it up quickly, and sustain almost endlessly.