Microcontrast - real or virtual?

While creatively-shaped apertures can give you "interesting" blur from a point source, I do think it's reasonable to say that the task of "good blur" is to minimise the visible structure in out-of-focus regions, and certainly not to introduce apparent visual detail. How much it matters depends highly on what you're shooting, but I think there's some objective aspect to the measure of bokeh in terms of what's "good" (although I guess there's a question about whether a flat circular bokeh or a gaussian one is "better"). That may not justify the level of discussion it gets, and there's certainly a subjective component to the way it's often reviewed.