Riven's Shield
As we all know, Riven's shield + dash can be very annoying, especially when the shield is worth around 700 health. So how about this change:
90/120/150/180/210(+100% Bonus AD) ----> 100/135/170/205/240(+70% Bonus AD)
That way, she gets a better shield early game, but her shield isn't as strong later on.