Rework Rivens mechanics.
Currently you have to abuse bugs and animation glitches to do well with her. If you play her as intended you will rarely win lane if ever it just isn't viable. and people complain about her being op because of the animation canceling and other bull shit.
I've played several hundred games using Riven, She's not an easy champion to play legitimately and she isn't a very strong pick (she has counters just like everyone else.)
My suggestion is to remove her ability to cancel animations and simply buff her damage to compensate. She's been over nerfed because of bug abuse when her real intended play style is completely worthless...
and possible reducing the cast time of her Q.