Regarding Riven
I don't play Riven. I enjoy the design of her character and her kit, but I don't play her because I'm bad at her. But since the forums are lit up with this discussion about her considering she was disabled for a while, I figured I'd offer up my opinion on what might make Riven a more enjoyable champion to play against, increase her skill cap, and introduce diversity to the champion:
Have Riven's shield scale off her BONUS armor.
No changes to the ratios or cooldown, just have Riven's shield scale off 100% of her bonus armor.
Tell me what you think.