Idol and Mirror feel a lot like they're the same story. Melissa has told different stories in the past.
Never Meet Your Heroes is about a man wanting to meet his rock star idols but backstage VIP passes are exclusive for women, so he dresses up as a woman and keeps doing that for months until he transitions. The Reluctant Adventures of an E-Girl stars someone who initially is reluctant to dress up as a girl but sees their donations increase, after which he sets donation goals for their future feminisation. The Reunion Prank is an hypnosis story.
They're different stories with only a handful of pages each. That forces Melissa to focus the story and to make them different from the next one. That allows her to focus on different paths that could lead to a transformation. If there's no need to make a fully three dimensional character, a guy with a bubble butt into a gym bunny story can be natural. A guy fearing male pattern baldness and accidentally taking too much anti-testosteron pills that lead to breast growth would also make for a nice short transformation story. A nice and quick in and out story. You'd think that's the kind of story sexy-story writers would know their way with. But we'll probably get a story with 11 pages focusing on a different limb before revealing the full transformation.
Don't get me wrong: some of my favorite MelissaN stories have been the short panel stories. I love the renders for Egirl, the corruption in Money Can't Buy Happiness, and the mental changes in Harley' Quinn's Biggest Adventure. But even among my favorites, there's no denying that we often get "whiny bland protagonist" in them.
Yes, the examples you listed (and speaking frankly, most of the shorts) have different
plot (and some include different mechanisms like hypnosis), but by and large the progression and characterization is largely the same. It's almost always this very superficial resistance where it gets hard to suspend disbelief that the main character thinks they aren't being feminized or can turn back, etc. I think Sweet Change was the most egregious example recently where a lot of us on this forum collectively were like "what?!" when the MC didn't seem to notice they were being feminized.
There's these knock of effects: It also means that for most of these shorts, 80% of the story has them complain and not accept their feminization (usually with a "I'm growing boobs?!" about halfway in), and then we do a time skip with a lot of surgeries and major body changes just for the last two pages. Now I know I'll sound a bit hypocritical as one of my biggest complaints towards (for example) sapphirefoxx stories is that the initial crossdressing is so passable they basically look like their final form, and it's just being told the surgeries are being done to catch up to how they already look. Or I'm also the first to complain that in Aphrodite's Mirror, we haven't had any transformation in a transformation story for quite some time. That said, I also do like being able to savor a part of the transformation.
Now granted, it would probably double the story's length. But taking Egirl as an example, the early half takes its time with being gradual goals. But every single surgery gets lumped into one milestone goal. That was super dissapointing. I would have loved it if hair removal was one, lip filler was another. Ass, hips, breasts, etc each got a panel. Especially if it were like each milestone, the MC had to pick a surgery, and so they were chosing ones that were least extreme, but slowly ran out as the donations kept coming in.
We all have our comfort spots. As a writer, I recently was going through my own works and realizing how often I fell back on certain descriptors or reactions by characters. So I'm not implying this stuff is easy. But it's certainly something that I've noticed and would love to see some variation off this pattern.
EDIT: So this reminded me: I saw a clip from a V-Tuber who was talking about how she realized/feels like being a streamer is turning her into a bimbo. It was kind of a joke, but I could see the nugget of truth where constantly relying on twitch chat to solve problems was conditioning her to not think for herself (and she was realizing that). In a non-sexy version, I definitely see that with a certain lolcow who constantly asks chat where to go and what to do in games. Would love a sexier, feminization take on this parasocial stuff, lol.