I like the direction of the new Essence Reaver and I have a few suggestions/questions:
Why make it %current cd and not %total cd, it feels odd to have a spell go to half it's cd in such a short time and the end just stretches out and the last few seconds the passive is basically useless.
It also feels like it makes weaving (I believe that is it's purpose) less efficient than "Use all 3 spells then go for basic attacks", so maybe strengthen the passive but limit it to the last spell used.
So I think it should look something like this: [...] and basic attacks refund 15% of the (total) cooldown of the last basic ability used.
As of now it also seems to not work with Riven's Q until she uses the 3rd iteration of it, even though it goes on cd with the first one.