Riven has been a topic of conversation for quite a while now. She has many different arguments associated with her. Some say she is perfectly fine others say she needs a change. I for one think she needs a change and fast. Her kit is very unhealthy. In my opinion it allows for almost no counter play. She has 3 dashes on a short cooldown, A shield that scales with 100% additional AD and its a dash, An aoe stun that scales with 100% additional AD and an ultimate that is a ranged conic execute that also buffs all her other abilitys for a couple of seconds. You cant match up to her in lane because of the shield and her mobility. She also has a knock up on her 3rd Q, couple that with her stun and thats almost 2 seconds of cc at level 2 with a lot of damage.
All this and the fact the she is RESOURCELESS means she can just spam to her hearts content. Once she gets a small bit of cooldown reduction you cant catch her. She is extremely difficult to gank because of her mobility. And if she gets a kill early (which she probably will) then its almost impossible to come back from that just because she has so much mobility.
I think she needs either a reduction in damage, a increase in cooldowns, a resource of some sort or a reduction in crowd control. She is simply too toxic to be left in this current state and is super annoying to play against.