“how are you going to make an ALIEN game built around the Engineers?”
“ALIEN games have always either been about gunning down xenomorphs or hiding from xenomorphs since the good old atari days.”
I didn't say that you only got to have them as enemies, you can have Engineers and other things. To just have Xenos when you can also include other things (like for example hammerpedes, what ever) would a missed opportunity and boring to me. What you can do is also to heighten the importance of the Engineers in the game, kind of like how they tried to make the Engineers important in Prometheus. Don't limit the franchise to just Xeno-monsters (monsters with Xeno-traits), it gets repetitive. I would like to see new things, not just things that get re-chewed so to speak.
“... they can have very diverse forms due to the xenomorph caste system/take on their hosts' traits…”
Yeah I know, fair enough, but there could be other things than just Xeno-like creatures. I would like to see new things and not just Xeno-isms that we've had since the late 1970's. Not that Xenos are bad, but because I'm more interested in new things.
“... androids would be no different then the human players just with white blood.”
Eh, no. Androids are synthetic, humans are organic, but I see what you mean. Maybe, it depends on how they are made. There could be ways to build them as characters, in ways that I might not be able to see.
About the Engineers, I would probably give the same answer to you as I did with the androids. What's good about games is that you can come up with new stories and therefore try new things, they don't need to be strictly tied to what came before. You can add things, remove things. In case those things are interesting enough they might show up in a movie sooner or later, who knows. I would rather get new things instead of just having what we've seen a lot of times before. Just because you try new things doesn't mean that you got to start completely new, from square one so to speak.
Your thing seems to be that they (Disney or what ever) can't introduce some new things into the franchise, since they are in your world not alien, as in the franchise. My approach is that you can introduce new things and still have it in the alien-franchise. This seems to be a thing where we have different opinions, but that’s alright.
In general, I would rather take something new, instead of having a movie or game with the Xenos again and again. Just because you add new things doesn't mean that it can't fit with what's already there. As long as it makes sense, then why not? Prometheus for all its flaws added something new (Engineers) but at least it tried. You can have something new there that connects things, but at the same time try new things.