Alien 3 already has one that came from an ox (or dog depending on which cut of the movie) so at least it doesn't need to be from people. Honestly aside from that they don't really get into the interesting DNA combination stuff too much. Could be cool for one that's like a breed of dog all specialized and whatnot.
Now I'm curious if a Chihuahua alien would be more aggressive than a regular Chihuahua or not
I think you hit the nail on the head with those points.
I've seen 5+ clones of Papers Please. I doubt that if you surveyed people describing the mechanics that they would be interested especially if Papers Please never came out.
For the original Halo they surveyed people who played who pretty much universally described the AI on the harder difficulties as being significantly "smarter". In actuality the only thing changed was enemies health pools and damage output and it was identical AI.
Gamers usually have a holistic experience with the games they are playing. There's definitely a place for user feedback to work, but devs don't look at a game the same way that people playing them do. Asking people who don't know how something works for feedback will give you perspective, but it doesn't necessarily lead to informed design decisions.