Riven has tons of bugs, not the Mordekaiser like but close.
Mordekaiser got reworked because Riot did not know how to deal with the amount of bugs he had and of course because it was asked to rework him.
Well Riven has the good amount of those on her Q.
Sometime her Q will avoid you resulting in wasting it and losing all the dps: https://streamable.com/7lznw
Sometime her Q will go backwards resulting in wasting it and losing all the dps and die: https://streamable.com/u4y8o
Sometime you will flash to Q enemy and knock them up, but not at Riot Games: https://streamable.com/0ma1f
Sometime your Q will just go towards your own death (backwards again): https://www.youtube.com/watch?v=2ia-cQbHns8
Sometime your Q will drag her towards the center of the enemy even though you Qd next to enemy: https://giant.gfycat.com/EvenEverlastingIbis.webm
Sometime you will drop all your dps because one of the Qs would randomly change direction: https://giant.gfycat.com/FormalImpishAmericanwigeon.webm
Sometime that would happen and you would die because of it: https://giant.gfycat.com/FixedSparseGar.webm
Sometime when Riven extends her Qs, the 3rd Q (knockup) would cause next Rivens Q to go backwards because of it: https://giant.gfycat.com/LoneFarAmazondolphin.webm
And again: https://giant.gfycat.com/VigilantBestCommongonolek.webm
And again: https://giant.gfycat.com/WhimsicalValidLeonberger.webm
And again: https://giant.gfycat.com/EntireLavishBlackrussianterrier.webm
Oh and again: https://plays.tv/video/5c17facf5d23ab047a/aha-alright-mr-q-we-will-go-your-way-?from=user
Sometime when you can extend your Qs (throw Q right after 3rd Q) and just when the 3rdQ is about to finish and you press it, will cause Riven to 3rd and 1Q right after, just with a one press and not two: https://plays.tv/video/5ba79f5fcc203dfee4/45-cdr-q-is-so-buggy?from=user
Riven is the most affected champion with unit collision: https://plays.tv/video/5b9ffb95a3107010cc/why-does-this-random-q-backwards-keep-happening?from=user
There is an insane amount of clips out there that i won't bother to post more since i think it's not necessary because i presented enough here.
I can't express enough just how many times these bugs cause myself and others to die, to miss a kill, to lose a lane and yes even a game. Hows that? Because Riven is usually the that engagee and when you flash into 5 people only to get bugged and Q backwards, you will die.
"But how did Riven not one shot them"
"But Riven is broken and you deal no damage, how"
Well this is the biggest reason. She deals 50% of the damage out of her kit, the other half usually goes away within bugs.
It has been years and Riot is still not responding to the major things and issues in the game. This game consists of mostly bugs and it's insane to me how people can expect me to be calm about patches when all i see are 10 skins per patch and few buffs, nerfs that are so useless and stupid. All the props to skin team, but i feel all the time that Riot doesn't care about these things as much as releasing new skins. They can simply just lower down the amount of skins released and focus more on fixing stuff. I do not want to buy skins with this state of the game. Please i want to see lots of information every patch about the bugs and fixes and less about other stuff.
Riven Mains Reddit post: