If we ever get a new Trek show, I think they need to do something new, that hasn't been done before.
And then it needs to do something that hasn't really been done since the original show as well: sparking the imaginatition and people's interest in space exploration.
Could a hard sci-fi route be the way to achieve that?
get a couple of scientific advisors on the show to make sure, that it deals with real phenomenon only.
When the Enterprise encounters new planets, stars, black holes, they make sure that the science is actually accurate to the best of our current knowledge with the surrounding drama making it wondrous and impressiv as it really is for cosmologists, physicists and biologists, etc.
Some concessions have to be made to keep some trek staples intact, like Warp Drive, but adapting it as closely as they can to real world science.
Actually this is pretty much what Roddenberry always wanted ST to be. At the time it came along, hardly any screen SF had ever aspired for realism or educational content, the exceptions being the film
Destination Moon, the '50s children's series
Tom Corbett: Space Cadet, and a few early seasons of
Doctor Who (more or less; that series was originally conceived as an educational show for children, and the Cybermen's co-creator Kit Pedler was brought onboard specifically to be a science consultant and bring more realism to the show). Most SFTV was pretty much pure fantasy. But Roddenberry wanted to make a show that was as naturalistic and believable as any cop show or adult Western, so he consulted with scientists and engineers and think tanks and tried to create as plausible a future as he could, allowing for the concessions he had to make for budgetary and dramatic reasons. He didn't entirely succeed at making it believable, any more than
Doctor Who's early producers did, but it was the goal he aspired to.
Later on, in TMP, he consulted with Isaac Asimov, NASA propulsion engineer Dr. Jesco von Puttkamer, and astronaut Rusty Schweickart to try to maintain realism, and on TNG, he relied on Rick Sternbach and Michael Okuda to bring scientific veracity to the show. There was some really good science in the early seasons of TNG. The periodic nova portrayed in "Evolution" is such a good portrayal of a real phenomenon that you could practically use it in a science class. The "Kerr loop of superstring material" as the source of the time warp in "Yesterday's Enterprise" is, aside from the mistaken use of "superstring" to mean "cosmic string," based in a very real theoretical model for a time warp.
And Trek was the first mass-media franchise to popularize concepts that until then had only been explored in prose. TMP featured the concept of wormholes, which at the time was pretty obscure both in fiction and real science until Kip Thorne revitalized the field with his research for Carl Sagan's novel
Contact; and TNG's "The Price" was one of the first mass-media works to pick up on the wormhole concept after
Contact came out. And "Evolution," again, was one of the first depictions of nanotechnology in mass-media SF.
So don't listen to those people who say that Trek has always tended more toward fantasy. That's the way most of Roddenberry's successors have approached it, in the same way that
Doctor Who's later producers abandoned its early educational aspirations and turned it into pure fantasy, but that's losing sight of Roddenberry's original intentions in creating the show.
Personally I'd love to see Trek -- or anything -- approached the way you suggest. Science fiction can be a marvelous vehicle for science education, a way to get people excited about the possibilities of the universe without misleading them about how it works. I've always felt it was a wasted opportunity
not to make science fiction educational.
And frankly, real science is so much more interesting. Sci-fi that ignores real science is very limited, because it just keeps rehashing the same old tropes that were used in older sci-fi. Real science keeps revealing new possibilities that nobody ever imagined before, and they can generate amazing new story possibilities. For instance, real science is now telling us that worlds like Jupiter's moon Europa and Saturn's moon Enceladus, or maybe even Pluto, could have oceans of liquid water deep beneath their crusts of ice and that there could be life existing in those depths. That is a far more wild and fascinating possibility than anything from
Lost in Space or
Star Wars or anything like that.
It's a mistake to think that using real science limits the imagination or creativity of science fiction. It actually expands it, because creativity needs material to build on. Yes, imagination is still vital, but adding more real ideas for the imagination to work on is like adding more colors to an artist's palette. TNG was innovative because it took real-science ideas like nanotech and wormholes and cosmic strings and exposed them to a mass audience for the first time. It expanded the range of things that stories could be told about. Later Trek just made up random names for particles and energy fields of the week, and was thus much more limited in its range of ideas.