The Way A Game Is Intended To Be Played =/= The Best Wa To Play A Game
With all this sudden hate of people like Yasuo and Riven and all of their animation canceling I want to introduce you to other game mechanics that were not intended but are staples of other games.
TF2 - Demoman Rollouts
For those ho do not know much about competitive TF2 the demoman class initially was designed to be a defensive character meant to cap and defend points. Although this still holds true his main strength comes in his mobility the is granted from his sticky launcher. Once perfected Demoman can get to locations faster than any other character. Although this is significantly easier with Soldier and rocket jumping, it was discovered much earlier on and appears to be intended, Although explosive jumping may be intentional the extreme mobility that Demoman gets was certainly not.
Super Smash Brothers Melee / Project M - Jump Cancel Shine
This was the first thing I thought of when I saw this hate all about Yasuo being able to cancel his AA into Q into E into whatever he wants. DISCLAIMER: I'm not even good at Melee, in fact I only learned how to wavedash across Dreamland with Luigi just last week however that still doesn't mean I don't/can't understand core mechanics.
Fox generally considered to be the best character in the game has this really strong move that comes out on frame 1 (which is the earliest possible time a move can come out on). This move whilst being able to come out very quickly it can be canceled by a jump as early as frame 4 (a whole 20th of a second later. Because Fox has a jump squad of 4 frames this means that the second shine will come out most likely around frame 5 to 6 which is still significantly faster than most moves in the game and it is very likely that the opponent will still be in hitstun. This means that if done against the opponents shield there is next to nothing the opponent can do resulting in a shield break or the cancel can be done into a wavedash which can result in a shine comboing into another shine. Although this does sound broken and unintended it still has a very high skill cap and overall Fox still have counterplay of being a fastfaller (which means he can be comboed easily in layman's terms)
(You can verify my information with searching up shine jump canceling or Melee Fox frame data)
Gen 1 Pokemon - Hyper Beam KO canceling recharge
To be frank this was just cancer but without it Tauros would not be nearly as strong as he is. The jist of it is if you kill the opponents pokemon you don;t have to recharge the next turn making i the best wallbreaking and sweeping move in the game. Thankfully they changed this in later games making it a competitively almost useless move.
Hearthstone - Execute not being being able to kill your own minions
Kappa :^)
RIP Artosis 2014 (I hope I'm not the only one who remembers this)
That's pretty much all I can think of on top of my head but I hope people realize that things that things such as animation canceling should be left in the game and I understand that my argument my sound very faulty or strawman but I personally think that exploits like these can make a game a whole lot more interesting and give it some flair even though they maybe inherently unbalanced (but at least with league you can balance it in other ways)