Geoff Dyer in Slate:
So less is more—but only to a degree. If the dress is very short then it is too obviously sexual. And then, because the wearer has to make sure that the dress is not too revealing, she is all the time having to pull it down or restrict her movements, thereby contradicting one of the essential purposes of the summer dress: absolute freedom of movement. (There is an interesting potential exception to this: the tennis dress is in some ways a sub-set of the summer dress but if it has to be accompanied by special underwear—underwear designed to be seen by the world at large—then the tennis dress stops being a summer dress and becomes purely a tennis dress. In short, it is possible to play tennis in a summer dress but it is not always possible to wear a tennis dress as a summer dress.)
A summer dress always looks best without tights or stockings. It is about limbs that are either tanned or in the process of becoming so. It is an advertisement for health and fitness (as such it is defiled by any association with cigarettes). The summer dress is only incidentally sexual; as such it is far sexier than the kind of fetish clobber or lingerie on offer in Agent Provocateur. Ideally it is even worn without make-up. In the context of ball gowns, where everything is artificial and heightened, make-up does not look out of place, but the summer dress makes anything but the most discreetly applied make-up look unnatural and unhealthy.