Ever since Riven been nerf, her Broken Wings are not as strong as they used to be. I'm not saying that it's useless, but this build provides more opportunity for basic attacks and life steal. You could sustain in lane much more efficiently and regain health to fight more battles instead of backing. So Since Broken wing got nerf, I decided to add that to Ki-Burst. Takes off one second cool-down, and it does a little more damage. Great for obtaining cs and last hit if you know how to use it properly. As for Flash, well I find Teleport much better in my opinion. I'm one of those type of guys that lane to farm gold so I could get all my items. Riven already has an amazing gap closer, her knock back with her q and her stunt is enough to incapacitate an enemy. Her Act of Valor is a dash, her Broken wings, both of them make her a bit faster.

So why use flash when I already have those abilities, "For flashing over walls to chase or escape?" Her Q can jump over walls if you know how to do it correctly. As for last whisper, I don't use it unless someone on the enemies team is going tanky, but it's not my typical build to carry. This build is suppose to give an ideal of a good build, I'm not going to put Last whisper if it's not guaranteed that one of the enemy team member is going god tank. Plus, the ideal is to aim ADC, APC, and other posible damage dealers, then you focus tank later with your team.

I'm thinking about editing this build to give a much in depth view to it, like adding Youmuu's Ghostblade, and other items that would go great with Riven and the way you want to build her. Hopefully, I'll be done editing it in a month.

Blade of the Ruined King is a poor choice on Riven. You don't even mention Last Whisper but this item is really important. You should max Broken Wings at level 9, not 10 and why you don't recommend Flash? Having a furthermore gap closer is just insane when playing Riven ...

This build for Riven is pretty good, Thumbs up! Nice one! GL and HF for anyone wanting to try her, great job ASAKUN!