I'm going to be very biased. You can tell with the photos I have posted that I love shallow D.O.F. For a full body shot that is somewhat close, I almost always use shallow D.O.F. I think it looks much better if the background blurs gradually. It gives the viewer a sense of depth and sharpness. Your photo will look sharp because your subject is in focus and the background is blurred even though in reality, this shot with f/4 is probably sharper.
A lot of people say that with awesome ISO capability with today's camera, fast prime isn't that important anymore. I agree with that to a certain point but when it comes to bokeh, it is just cant be replaced. I believe if you had shot this with a 35 prime at 1.8, it would have been a stronger photo (or even at 2.8 with your zoom lens).