Unpopular opinion. Riven should ONLY have a reflex shields.

What do I mean by this? Well riven's AD scaling Dash/shield should only last a fraction of a second. Given how strong the shield is, a .25-.5 second duration would make using this shield very rewarding for good plays, and not "hey here's a shield you can sit on repeatedly and forever."

It requires no skill to spam everything like she does, and heal as much as she does, while being able to just shove a guardian angel in her build with no downsides. It honestly doesn't and I'm sorry to tell you this, but with I would argue that i's no longer necessary for her to have a shield period.

So let's either remove the shield all together to make trading against her fair, or make it a reactionary shield so they're less likely to just throw it out whenever. Having to thinking about your play is NEVER a bad thing.