[{quoted}](name=o0O Madoka O0o,realm=NA,application-id=3ErqAdtq,discussion-id=Zt0aGGJE,comment-id=0004,timestamp=2017-03-22T18:30:55.518+0000)
Generrally speaking, in a balance sense, no.
GP and Fiora damage is conditional: GP relies on chaining E, Fiora relies on procing passive and ult. They both have 1 "get out of jail for free" card because of their uncertain damage output, allowing them to outplay.
Mord is outdated, so I'm not gonna take him into balance account. Think about the old GP and Fiora before rework, they have lower damage potential but higher reliability, making them really difficult to balance.
ADC damage on the otherhand, is impossible to outplay. Kog' Maw can pop his W and auto you to death within a second in late game, Tris and Jinx works similarly. Thus they must be vulnerable to attacks to balance it out.
Vayne isn't a hyper carry in a sense like Kog'Maw, Trist, and Jinx. Her damage is more condtional (ult and 3 hit passive), thus she gets stealth in ult, and E to outplay (both on high cd), she cannot murder you whole team in seconds, she's more of a mid game-ish adc, capable of shredding tanks while other hyper carries are still finishing their builds. The hyper carries are all about the late damage and clean up teamfights and take turrets.
Vayne is rivaled or exceeded only by Twitch as a late game carry.
Her strength late game comes from being largely immune to the common strategy of isolating the ADC and killing them. There are few champions who can solo kill an isolated Vayne late game. She also doesn't have to build a last whisper item (there is a reason that any champion who can afford to drop the item like Yasuo, Vayne, or Master Yi does), so she can itemize for some hot burst (like with her crit build) or with relatively more durability than an ADC, like a maw and a GA combined. She just has enough damage built into her kit.
I do think Twitch is stronger late game, but there aren't many champions who can beat the ability to melt an entire team by auto attacking.