After a strong start categorizing the ways sex is used in games -and doing so in a way that keenly differentiated this article from the way something like Fox News would deal with sex in games- I found myself disappointed by the author's conclusions. Could he honestly believe that a nude Alyx would be a good reward for completing HL2, and that this wouldn't cheapen the product horribly? And what about the bizarre rant, apparently against BioWare or Valve for their "transparent agenda" to, say, depict women in games as something other than trophies?
I think the place of sex in video games is very similar to its place in movies. A few do it well; most are gratuitous and don't help the story, but still help to sell the product. Sometimes a sex scene works best when the sex is implicit. The first God of War had frontal nudity as Kratos walks away from his bed and the women in it. This worked for me because part being a Greek (-styled) hero is having an insatiable appetite: whether for bloodshed, for feasting, for drinking, or for sex. The scene helped sell to me that Kratos was this type of character, and would fit in next to Heracles and his larger-than-life ilk. But this was accomplished with brief frontal nudity, no actual sex was witnessed or performed.
Actual sex gameplay seems like a foolish idea outside of porn games or comedy games. There's no situation I can see a playable sex scene resulting in anything other than humour or awkwardness.
I think that sex as a narrative tool in an RPG like ME or DA would be better if it was somehow kept from the player that it is an inevitable result of adding enough "affection points." In a game that gives the player a choice of partners, even between just a few characters, I find that I see the entire "romance" bit as too obviously artificial, and can't really get into any of it. Sex as a narrative tool could still work in a linear, choice-free story, which I would probably find more compelling precisely because it is not sex as a reward.
Speaking of which, sex as a reward should probably be limited to porn games and comedy games as well. Or to shameless games like BMXXX or DOA-Beach Volleyball: that is to say, games that are to "interactive art" what Baywatch is to "compelling drama."