I can't comprehend the gripe at all. Why would "nudity that didn't show anything" be better than "clothing that doesn't show anything?"
Fortunately, one of the other commentors on the piece totally gets it -- concealment creates the notion of there being "something to be revealed." The whole point of the pic is that Comfort is going to be more dressed in the pool than she is in everyday life, and that as she takes off her shirt, the viewer, whomever it might be, gets a glimpse of what little of Comfort's body we never see.
But once the shirt is gone, well, the jig is up so to speak. Not to say that Comfort couldn't be sexy at that point -- I'm sure Dover would have a lot to say on that subject -- but it would require a lot more explicit kinds of poses/situations than I am willing to put the SJ cast into. As it is, the whole notion of the "Cake" portfolio took a lot of "coming around to" on my part because I don't want sex to be what SJ is about. Not because I'm a prude, so much as because sex just isn't really that interesting a topic.
Oh well. Fans are weird. :)