What is the reasoning behind the Vayne buffs? (not a complaint, actually wondering)

Greetings,

First of all, I know such a thread can come across as a whining thread, especially since those are all over the boards, lately. However, this is a legit question.

I am not a good player by any means. I never play ranked, and I estimate my level to be around mid-silver AT BEST. However, for a player such as myself, especially since I main tanks and bruisers, Vayne is a nightmare to face. I cannot count the times I lost a game simply because the enemy Vayne got a bit ahead in the early game and turned into an unstoppable monster afterward. While such things can be explained in part by the fact that people at my level of play do not know how to fight back against her, she still looks to me like she is a good champion either way. Statistics show her as having a very good pickrate (almost 20%, she is very popular!), a very respectable winrate (a little over 50%, which looks very good considering she is so popular.), and a considerable banrate (around 13%). The point being, she looks like she is in a good place overall, being often picked, still winning a good share of games, and even feeling threatening to a good part of the playerbase.

The idea being, she truly doesn't strike me as the champion who could use some love. That's why I would really enjoy to have a rioter explain to me what their reasoning was for thinking about buffing her. As in, they are likely to have much more accurate data and a better grasp on the game ecosystem than I do, so I am certain there is a reason I am simply not understanding, as the low-elo scrub that I am.

Any answer would be appreciated, I could use any insight!

Thank you in advance!