The reason I personally prefer B.H.A.s is because I enjoy Trek the most when it boils down to its most basic element, two or more people talking to each other. I'll take a Human arguing with a Cardassian over the most elaborate, amazing non-humanoid alien ninety-nine times out of one hundred. (That's not to say I don't enjoy the latter!)
I don't think a character needs a human face to be relatable or capable of interesting interactions. There have been plenty of movies or shows that have made audiences care about nonhuman characters, like E.T. (though I hated that movie) or
Farscape's Pilot, say. And of course, radio shows, animated productions, and audio dramas have been making audiences care with vocal performances alone for generations.
I think sometimes it can be easier to care about a nonhuman character, because they don't come with the kind of baggage and preconceptions we put on humans, and so we can connect to them more purely, like we do with pets. As for myself, I have a quirk that I tend to be particularly fond of disembodied A.I. characters in fiction, like HAL from
2001, KITT from
Knight Rider, and the like.
I think it wouldn't really be Star Trek anymore if you had to so severely change those elements. I think the reason that the "shorthand" of those story aspects exist in the first place is because the writers and producers realized they needed it in order to make it all work, and if they had to get deep in the weeds on how the Enterprise makes an orbital injection or the specifics of atmosphere conditions during a landing party that it doesn't work for the story as well as just the captain saying "standard orbit" and "class-m planet."
Okay, you're operating from a common fallacy right there. Nothing about hard science fiction requires you to explain things in depth to the audience. They just have to make sense for those viewers/readers who know the difference. For everyone else, it doesn't matter either way. The important thing is that the
writer understands the science and can build the world in a coherent way. As far as actually presenting it to the audience is concerned, it's fine just to treat it as a fait accompli. If you get "into the weeds" and distract from the story, you're doing it wrong.
Just look at
The Expanse, say. That's about as hard-SF a show as there's ever been on TV, but it doesn't spend time giving lectures about how the science and tech work, it just
shows them working and lets them speak for themselves.
Heck, TOS actually did that with warp drive. Most contemporary SFTV in the '50s, '60s, and '70s just had spaceships making interstellar journeys with ordinary rockets, or did things like
Space: 1999 having the Moon simply drift from star system to star system (with infrequent handwaves about falling through space warps). But TOS did its homework and determined that FTL travel would require something like warp drive, a consequence of the equations of General Relativity, and that such an advanced and powerful drive would only be possible using the ultimate energy source in the universe, matter/antimatter annihilation. That all comes from hard science and theoretical physics, but they never stopped to explain to the audience what a spacetime warp was or what antimatter was; they just
used it. As Roddenberry said in the TOS bible, a police officer doesn't stop to explain his gun or his patrol car to the audience, he just uses it. But that doesn't mean the gun and the car aren't based on realistic principles. Shorthand doesn't mean making up nonsense, it just means brevity in presenting what you know.
As for what makes something
Star Trek, Roddenberry's fundamental goal behind its creation was to treat science fiction seriously and maturely, to create a world that was more grounded, naturalistic, and believable than the fanciful children's shows that dominated SFTV of the era. Though taking dramatic license with things like Earth-parallel cultures and humanoid aliens was necessary for budgetary reasons, it was an unavoidable compromise, not the point of the exercise. Aside from those things, the goal was to make the show as believable as possible, at least on a character level, but as much as practical on a technical level. So making the world more realistic would make it more like what Roddenberry aspired for
Star Trek to be, not less.
I think Trek's ban on genetic engineering fits with Roddenberry's views on secular humanism and Trek's belief in the perfectability of humanity through social change. Roddenberry's vision for Star Trek is based in believing in humanity as it is and of humanity growing to be better as a culture and society, not becoming better by being given qualities through design.
I don't think that holds up, since the ban wasn't introduced until years after Roddenberry died. And early TNG did not have that kind of anti-transhuman bigotry, but on the contrary was willing to explore transhumanism by giving us characters like Geordi with his superior artificial vision, and Data, an entirely artificial being exploring his humanity.
Star Trek has historically been a show that celebrates the potential of scientific progress to improve humanity, rather than falling into the usual mass-media sci-fi cliche of treating progress and innovation as scary and destructive. That's why DS9's retcon of a genetic engineering ban was so out of character for the franchise.
I mean, yes, "Space Seed" did depict genetically augmented superhumans as dangerous, but TOS also portrayed artificial intelligence as dangerous or evil (with the exception of Rayna Kapec, who was just doomed) while TNG took a more optimistic view of it, in keeping with 1980s-90s culture's greater familiarity with computers and the resultant loss of fear toward them. In general, science fiction literature of the '80s, '90s, and beyond embraced the potential of transhumanism and human enhancement. Whether it depicted it positively or negatively, it was increasingly taken for granted as part of humanity's likely future. I'm convinced that's the real reason for the ban in DS9 -- because the producers realized how backward Trek's futurism had gotten by failing to acknowledge transhumanism, so they tried to handwave a feeble excuse for its absence.
After all, there's nothing about secular humanism that objects to the idea of transhuman augmentation. After all, secular humanism is the belief that we can use our knowledge and invention to better ourselves, and that's exactly what genetic engineering is. The objections to it are more likely to come from the religious side, with its rhetoric about the evils of "playing God." The notion there is that we're God's children and must defer to God's will. But to the secular humanist, humans are responsible for ourselves and have the power to become whatever we choose. Genetic or bionic augmentation is something we would choose to do in order to better ourselves, an application of our own ingenuity and inventiveness, and from a secular humanist standpoint that's a good thing, as long as it's shared with everyone instead of hoarded by elites.
