__________________________________+++++++++++_____________________________________________________
"NTR is essentially about humiliation, and therefore making the victim as inadequate as possible, is a fairly necessary component of this genre. If Devs were to make characters like you suggest, it undermines the whole purpose of NTR, making the players share the shame and inadequacy of the protagonist's inability to satisfy his partner, leading him to being degraded when she cheats on him with other men, who are all more well-endowed, masculine, dominant and sexually experienced."
You have hit the mark with David, Anna's husband, but perhaps not in the way you define NTR, at least not with this story. As a character David is average as far as males go, a good husband, mild mannered, and honest. But Where I think the developers are going is that Anna discovers another side of herself, and David can't scratch that itch that she will discover. We still have to get a clearer picture of Anna inner personality.
We already know the "big dick" trope is in the mix with Chris. Yes, most women prefer "average" dick sizes (6ish inches and etc.) But yes, it's also true every now and then a woman wants to experience big. So already David doesn't compare to Chris and Chris has more experience.
Jake, has looks and perhaps more techniques the David. As far as the plot goes, you have an everyday trope going. A co-worker lurking in the background in a troubled marriage. Now does the Jake route truly qualify as NTR? What if Anna and David were still happy in their marriage and Anna cheats for whatever reason? It's the main reason why I don't care about the Jake route and likely will not play it.... Its conventional, predictable, and boring.
It's no coincidence, that in all Japanese games featuring NTR, the male protagonists are pathetic weaklings. If you're into NTR, you don't want a player character who could easily be one of the antagonists, you want someone who is very obviously a loser. That's what people who generally play NTR games want, which is why most Devs create them that way.
Going back to your definition of NTR, David doesn't qualify as "pathetic," but maybe can be called a simp at worst or just plain. Where the game can take on NTR, is what Anna discovers from the other male love interests as I mentioned. The problems are first gamers' impatience with content to get to the "good parts." But to really nail down the other routes the release after this coming one will have to be a huge in content to explain Anna if it's the developers' goal to get some action started.
Now the Hank and Marcel routes are easier to define and develop. Corruption and submission make for an easy plot to follow with Hank. Still needs some background work to explain Anna's submissive nature to allow herself to be used by Hank where corruption evolves Anna's character. And all Marcel route needs is plausibility of bringing them together.
NTR is like having a fetish, so if for instance you were a person who had fetish for rubber clothing, wearing leather instead wouldn't do anything for you. It's no different for this.
You mentioned "fetish." The only way one can explain Marvin and Grant routes are what secret fetishes we are not aware of that would allow Anna do go down those rabbit holes. And the only way I see that is backstory and flashbacks to explain Anna's inner thoughts and dare I say "Darkside."
