Can somebody tell me what Riven's weakness is?

She has great mobility mixed with a lot of damage, don't see a lot of champs like that.

She has low cooldowns and scales immensely with cdr.

Her shield scales with AD, meaning she gets tankier with more damage built.

She has 2 steroids, her passive and her ult.

She has a ranged aoe execute.

She has 2 forms of CC

Resourceless

Now I didn't lose to a Riven just now which is why I'm QQing about Riven, but from making Darius threads, the thing I have seen is that everybody seems to say "If you get in range of Darius, you are dead"

Isn't Riven the same thing? She gets in range of you and you're fucked.

Darius doesn't have the mobility to catch up to you like Riven can, Riven also has MORE DAMAGE than Darius EARLY game. Riven is better than Darius in every category except he has true damage and Riven doesn't.

But with the amount of damage Riven can dish out, combined with her mobility, and her lack of a resource, it doesn't amount to squat.

Riven is supposed to be scared of Darius in her lore, wtf why she would rape him.

Riven is stronger than Darius at all stages of the game, yet he is QQ'd about more.

What is this champions weakness?