I think Vayne needs an update or a VGU
To be straight to the point, this champ almost always blows.
Her niche is a late game tank buster/(duelist?). So the common thing I hear is that she is meta when tanks are really strong. Which I think is pretty inaccurate. The times she meta when lane bullies in the bot lane aren't meta or somewhat decent. That's because how much her laning phase sucks. Most ADC's already fulfill the role of tank busting with just the items currently available in game except they actually get to have a laning phase. Yet the way Vayne's current kit is creates a situation where if she is able to have a reliable laning phase she becomes OP and pick/ban.
In her current state, I hate seeing this champion on my team because it means I have to hope bot lane doesn't just get stomped on while remaining relevant which spoiler alert rarely happens. She has a lackluster laning phase for power later on that already can fulfilled by other ADC's I don't even think most people play Vayne for her scaling but for the playstyle. That what her gameplay update should preserve in exchange for some of her scaling. Lore wise she doesn't even play well with others and might be better suited as a jungler instead of the bot lane role. Just my thoughts/rant.