Just gonna point out again, it would kill the atmosphere and ruin a vast majority of what makes HDN, HDN. Heck, there is that core restriction that the person in charge of HDN promised it would be an all female cast. If anyone really wanted to have males in the game, I just wanna be fair and give an example of why that wouldn't work:
----- Warning: This is a very long post, feel free to skip over it if you feel this doesn't apply to you -----
Example Outline of the Game's Plot:
I. Starting roughly 3000 years after Mk2 or even V, the goddesses are somehow defeated by an evil deity of some sort.
II. As a result, they are forced to flee Celestia which heavily corrupts it under the evil deity's tyranny.
A. As a side effect, their HDDs have lost a bit of power and it's becoming difficult for them to sustain themselves.
B. To avoid potentially dying from a lack of rapidly declining shares, they decide that they need to find individuals strong enough to house them. Sort of like symbiotic life support. They sleep within that person's body, they give them a fraction of their powers to fight with. Once that's accomplished, they can continue their search for a power great enough to defeat this great evil (probably Arfoire, I'll leave that up to any one who reads this) using their chosen warriors as their fighting mediums.
III. Going off of that, they split up on their particular lands in search of someone strong enough to house them. (And therefore the goddesses initially as playables would be like a summon that lasts for a certain amount of time game wise that would have high stats that just tear up everything except the stronger bosses until you perhaps unlock their actual characters later on when you acquire this new power that they're looking for)
A. The goddesses each acquire someone to house them. These would really be the only reasonable male characters you could even potentially squeeze in with a close to legit reason. (And their only link to the story is that they are for some reason the only ones who the goddesses feel could best house them which in HDN, seems like a total fallacy. Especially since I'm pretty sure IF would fit the bill for at least one of those four roles)
See what I mean? By numeral III you've already encountered something that is easily countered and corrected by the current laws of this fictional universe. That's pretty bad since that's just the introduction's super expanded skeleton. Worse yet, that totally implies pairings EVERYWHERE. Four males, four goddesses? It makes several possible endings incredibly obvious and predictable. While this is only one scenario, most of them you have to admit would likely wind up in this situation or worse: a harem. And if they added more male characters, what's their relevance to the plot? If we already include even just a majority of the current HDN cast (not even all of them, just some) that cast would be HUGE. It'd be almost impossible to give anyone a meaningful role to play in the plot without that game being ridiculously long. And, it'd be equally difficult to give each character a justified purpose for their existence as a playable. You'd have a large handful of characters who hit the neverused tier while there's only a select few who the players will actually use in a real fight. (I could be wrong, their might be a way to balance it out and everyone's got a preference but still, it's a likely result) While I think a long game with a meaningful plot and sub-plots for each character would be pretty cool, the likeliness of something of that magnitude being developed in real life is pretty low at the moment in my opinion. (Given that to make a game that long with good graphics and gameplay would probably cost lots and lots of money
I won't be closed minded, and perhaps in a spin off (as much as it'd certainly risk losing my purchase and many others' purchases I'm sure) something akin to this could work. But for now? I'm just gonna say that with something a little more straight forward presented as an example, it's likeliness of working with the current set up is incredibly low and would probably require a loosely associated spin off AU that breaks a lot of the rules currently in place for HDN's universe and replace them with new ones. Sure, you could use the current universe, but again given the current set up, that destroys the game's thesis of being an all female game. Bottom line, it just wouldn't be HDN anymore.
For now, I'll just stick with HDN how it is and the fanfics that don't destroy the laws of its fictional universe. In another franchise, something like HDN with a mixed gender cast would be cool, just not on HDN itself is what I'm trying to get across I guess. Just wanna say, this wasn't meant offensively.
Again, I apologize for rambling guys.
(Noob warning: Sorry if writing something this long is against the rules or something. I just figured the argument and the evidence behind it should be legit to be fair)