I do agree that Macaw could be great for prototyping, but I'm adamant that it will be the death of quality code and websites if designers begin to misuse it.
I think you misunderstood me. The two roles (designer and frontend developer) are becoming more disparate and specialized. In the future, designers may not be coding full-fledged websites. Your ideas make sense to you now because you are both coding and designing. But, I believe there will come a time in your career where you will have to choose to specialize in one or the other. If you spend more time in design, you will find that your frontend peers will zoom past you (and vice versa).