Using sketch / photoshop these days gives you "Copy CSS Attributes" functionality for most of the elements, which is basically 50% of your CSS, the rest is layouts ( super easy these days with flex box / grid ), media queries and probably some more.
I agree that Cascading part of the CSS is very troubling, but I don't think functional CSS solves it in an elegant way. Actually I think it's hardly readable and confusing :(
As of the argument that you don't need to write CSS properties anymore, I would suggest using a plugin like Emmet [1].