Based on my (s)experience with the mass effect series, I find some of Jim's complaints valid, some less so.
On the valid side, I never thought about the whole NiceGuy/Frienzone implications of the romance options, but I suppose the romance minigame does have an input/output feel to it. And within a single game, the sex scene is indeed portrayed as the capstone of the whole relationship, no further exploration of the emotional side is given. And yeah, for all their high-and-mighty statements, titilation is a factor of their appeal.
On the invalid side, I don't recal giving presents to be a part of the Mass Effect romance options. It was about talking with the partner and getting along with them. That is a real and neccesary part of a real relationship too, though it is true that it shouldn't automatically result in a romance. But, especially in the earlier games, it wasn't. There were quite a few crew members you could talk to and befriend, but who would never sleep with you. Only some apparently kind of liked you, and would consider you as a romantic partner if they "got to know you". Admittedly, this fell a bit by the wayside in later games, where you could romance everything with a pulse and a roughly human shape. And where they started adding pointless characters that added nothing to the plot to your crew, just to give you more shagging material.
And another point is that you could, if you looked, find a bit more of an overarching romance-arc if you played several games. My fem-shep dated Liara in the first game, but since I didn't own Lair of the Shadowbroker, she's not a romantic partner in ME2. I didn't feel like romancing any of the other characters, so I did nothing. And that resulted in a short scene with just Shepard in her room, wistfully looking at a picture of Liara. No sex, but romance. It's a small thing, and it would be nice if there'd been a little bit more of that overarching feel, but it was there.
And in a character-driven RPG like Mass Effect, I'll say that yes, titilation aside, I am interested in the romance options for the romance. Let's face it, if you just want to see sex, there are much easier ways of watching much more explicit material than these games will ever give you. I wanted to do the romance plots because I liked the characters and wanted to see them hook up.
(Side note: On my first playthrough of ME3, I didn't have my old saves. I noticed that my favourite character in the team, Tali, was now a possible romantic partner, so my clean-slate male-shep tried to woe her. And then the Geth-Quarian conflict exploded in my face because my actions from ME2 weren't saved. And my paragon Shepard could not just let the Quarians, who'd been following the lead of the trigger-happy maniac the whole time, just wipe out all the Geth. So I helped the Geth, thinking the Quarians would pipe the fuck down once I did. They didn't, they got wiped out and Tali killed herself. A punch in the gut that was, let me tell you, but I refused to reload my save. That was my character's moral decision, and if that meant the girl he loved died, he'd just have to live with that.)
So, bottom line, there's something to Jim's complaints, but I don't think sex scenes can't add anything to a game. I don't know an easy way to fix the give-the-right-answers-in-X-conversations-and-get-laid problem without making the game arbitarily dump two characters in bed, but a few more major characters who just aren't romantically interested in your character might downplay the suggestion that sex is simply bought with sufficient nice answers. And don't treat the sex-scenes like a the victory-screen of the romantic minigame, equivalent to the good-ending cutscene of the main game. Show more of the emotional part relationship, especially afterward. Having it carry over to the sequel is a plus.
