Think about it. Yasuo has an almost anime like lore (as said by uberdanger) and if you make that into a cinematic then it will be kick ass. To watch him run from his once friends and then cut them down in order to live another day. And then the sad part of the story when he kills his brother. 
Make it part of the Ao Shin intro vid, and have that part of yasuo's story, and then make one about riven as well, and then kinda play them side by side until they are traveling and they both see like a swirling vortex like a tornado and then at that point it zooms out and goes to one screen showing both of them and they enter and in the center of the tornado storm vortex is ao shin... it would work cause both of them use the wind and such, and ao shin is the storm dragon... but make the plot of them traveling revolve around the wind portion or something idk
I would love to see the emotional turmoil for Yasuo, The character plot would be so smooth with little plot holes.
I'm not a big fan of Yasuo's lore to be honest. It's relatively straightforward and the whole 'exile' thing doesn't really appeal to me, especially when he doesn't bring anything else to the table (apart from if he is one of the greatest swordsmen in Ionia or something).
I think they should do Ionia cinematic in general (hopefully another lore video).
I think they should make one where some mysterious champion (with a pretty horn) walks around and heals people. That sounds nice.
What's with the down-votes? While I certainly think there are stories that should get a cinematic before Yasuo's, I don't see what is wrong with the OP suggesting that his favorite champions gets a cinematic.
I don't think anybody cares about that, besides few people like you.
Normal people just like it when riot publishes some random cinematic, and they don;t care about which champion is it.
Much rather see cinematics for each year of the Harrowing timeline before a lot of things. The movement of the blackmist, Bilgewater, all the champions and fleets that have fought against it, etc.
