Thanks, I like having decent discussions with people, it's fun and you often learn something from it.
Cait late game is definitely an underrated monster, I forget how strong she can be in the right hands and with the right build. Most Cait players hang back and just poke, but some play basically like Vayne, going right in your face but still dodging skill shots and dealing massive damage in single shots.
I don't think Cait is OP, and in fact, I think playing her well is even harder than Vayne, as it's kind of like exploiting her mechanics in ways she wasn't designed for, but just happen to still work, the main difference being longer cooldowns, so she won't often 1v5.
As far as the game is concerned, there are champs worse than Vayne, much worse, who snowball or hyper carry on much less amounts of Gold (cough cough Akali), but I understand why people dislike Vayne, especially in a season or Elo that is bad at closing games early.
Even if Vayne is equal to other Adc's late game, one difference is most of the adc's are doing well and continue to do so when they get that strong, Vayne can do so poorly early and mid, have 1 kill ad 8 deaths, and around minute 35 start going 1v5 all of a sudden. It's just frustrating to lose to someone who you're better than, due to the nature of their powerspikes and kits.
Currently i feel the same about Yasuo and Akali, as champs that can fail miserably, but powerspike suddenly
- Akali level 6 no items and half farm can suddenly 2 shot most mid laners, and tower dive if she earns 3 kills
- Yasuo can lose his lane quite badly, but powerspike around minute 25 without any significant amount of gold and become a massive impact in fights and eventually hyper carry. Plus he actually has a strong early unlike Vayne.
I think the only other reason to have a legitimate reason to dislike vayne, is she hasn't got much in terms of identifiable weaknesses. She has playstyle weaknesses, like pressure her early or force team fights so she can't split/farm to catch up. But if you catch her out, you're ahead in kills and farm, you land your full combo, she survives with 100 hp, then proceeds to beat you with life vamp, cc, hyper mobility, infinite chase, burst damage and dps.
- again, higher elo will know that, despite her being behind, it's best to force teamfights then split and chase a Vayne solo, or even duo, but lower elo get cocky and overestimate their leads.
It doesn't make them bad scrubs or worthless, but most people have to experience this before they learn to play against it, because on paper it just doesn't seem right, then someone else on their team makes the same mistake and it's frustrating. The only unhealthy aspect about Vayne is that, just like Teemo, she just frustrates people, she herself, is not THAT OP.
Edit: I think their should be a rule against Vayne like the no chase rule against Singed, to stop people falling into Noob traps