There's a lot of ACT H games that have great ideas on implementing sexual attacks without charging players a fun tax. But ultimately your preferred hentai system is going to be subjective, some people prefer battle fuck others prefer the combat rape and so on. I've seen 3D H games like that Curse of the impregnation princess game to fulfill a seamless entry into the sex without consequence, there are still ideas on the 3D side of things that are catching up to some of the hentai RPG sexual combat or in general hentai systems, we just need to wait for them. I like the way Bioasshard does it's sex, even if the struggle mechanic is antiquated now to how others do it, I just wish it complicated the inflation in a meaningful way or added am information stats page for all the various sexual activities like the RPGs do. Everything else is more of less up to the creator's vision for what they believe to be a proper H game.
Honestly, at least when not comparing it to 3D Action games as a whole (of which most still have pretty lack luster ways of implementing the actual sexual mechanics, if even functioning as games at all), what I was mostly pointing towards was the fact that there are very few actual 3rd person Shooter H-games. The only one I can think of off the top of my head that has actual sex tied into gameplay, and not just on defeat, is pretty much Too Much Light, which also handles things pretty similarly thus far. Of course, this isn't really meant to excuse the fact that these games have what I feel are less than optimal ways of tying the sex into gameplay in a meaningful way. Even in the 3D, and largely 2D space as a whole, most games either venture too much into the sexual side of things, largely focusing on the hentai to the detriment of actually being a game, or focus too much on the game side, giving little reason for it to even have any hentai tied to it, like a certain third person shooter I can think of right now with urine/toilet play, but can't for the life of me remember what its actual name is. Even, assuming the one you mention is the same one I'm thinking of, having you act as a somewhat 2d character on a 3d plane, does well on the H-game side of thing for sure from memory, but I couldn't bare to play it for longer than a few minutes here or there just due to it being a mess of a game, and somewhat buggy if I recall (pink haired girl with a sword in a village is all I can really remember ultimately.). While I definitely think it has a super solid premise as far as a game goes, and did deliver pretty well on the actual hentai side of things, it just kind of fell short in every other regard in what was somewhat of a disappointment for me really.
That said, stuff like Succubus Heaven has been one of my most anticipated releases for an H-game in ages, and its a 3D soulslike dungeon crawler with three characters, with the H tying well into game play, both as a punishment and as something that feels good to play around as a whole. I suppose my main point still just boils down to while Bioasshard has a little ways to go, and if they do give more meaning to the infection system, has a solid place to build off of right now. Even if they decide to go a new direction in tying in the sexual aspects of the game to the gameplay itself, all it'd ultimately take is a few tweaks here or there and the system could work really well. Granted, since its one of the few third person shooter hentai games out there I know of, aside from a couple other gems out there, AND its taking inspiration from one of my favorite RE titles, I'll definitely admit I probably have some bias in terms of giving the game some leeway, and it has a little ways to go both on the action front, as well as the h-game side of things, but I think it genuinely does have the solid building blocks to get even better from here, and what is there is pretty enjoyable. But then again, if you're looking at it in the sense of something like what RPG's tend to do, with corruption and stat tracking, neither seems to be all too difficult to add here if people pushed enough for it, especially corruption and tying it into the infection system potentially, making it more difficult to escape grabs, and possibly just leading to outright game overs when being grabbed with a full bar, potentially with some variation that's far more lewd or even 'ahegao'ish to really signify that fact, just to add some more weight and depth to it all. I definitely understand where you're coming from with that perspective anyways, and I'd love to see stuff like that implemented, but I do think they need to solidify the game first before diving into details like those, and get closer to completion of whatever the main game is going to look like, as this game realistically, if it does get finished, probably won't be done for quite a long time, several years even really considering the scope and the size of the development team working on it.
Regardless, yeah, there is certainly some bridges that could be crossed to add a bit more depth and meaning to hentai in plenty of H games as a whole, especially 3D ones, we'll get there sooner or later. All we can really do at this point is suggest ideas, and keep an eye on whats being made, and I can at least say this game has shaped up more than I initially expected it to, so I'm at least hopeful for the future, even if its definitely going to take plenty of patience to sit it out to completion. Thankfully, being in this space for a while, its something I've learned well at this point, Project X probably being the greatest lesson I've had in forgetting about a game, just to come back to it a few months to a year later and seeing if theres any surprises in store, or if its just still stuck developing the next update. xD
TLDR: Was more focused on 3rd person shooter h-games, of which there are few examples out there, much less really good ones that blend both H-mechanics, as well as game mechanics, and Bioasshard with some yet not fully developed mechanics is on a solid path to really shape up even more as time goes on. Also, side note, if you enjoyed The Curse of Impregnation, props to you as I really wanted to, just couldn't find a ton of joy in it in the end. Hope they make a sequel and improve some of the games flaws in the future.