Mary McNamara for the LA Times (may contain spoilers):
...as important to theme and character development as it may be to point out, in case we missed it on the nightly news, that some men enjoy paying for sex and treating women as sexual furniture, HBO has played this card so often that the obligatory scattering of reclining females with their blouses open or absent now elicits laughter more than shock or titillation.
Prostitutes and brothels are obviously and regrettably simply vehicles to work the R rating, to give viewers, if you will pardon the expression and maybe you shouldn't, more bang for the buck. Which isn't just gratuitous and ridiculous, it's lazy and sexist. For all their many functions, women's bodies are not props and prostitution is not something that should be regularly relegated to atmosphere.
It is also hugely unnecessary, an example of HBO uncharacteristically underestimating itself. Perhaps there was a time when people subscribed to the channel in part for the F-bombs and the nudity, but that time has passed. Naked women rule the Internet, "Doctor Who's" beloved Billie Piper plays a call girl on Showtime for goodness sake, and reality TV has redefined prostitution (is it truly more moral to sell one's soul than one's body?). No one subscribes to HBO because of the nudity, gratuitous or not.
George R.R. Martin's novels certainly don't shy away from sexual content, but it sounds like the show's producers might be laying it on a bit much: this isn't the first critique I've seen of the series' use of nudity.