....the Feds should never have to worry about any threats again. Off the top of my head.
Why no need to worry? This tech came from folks. Those are a pretty big threat, especially now that our heroes do have their tech!
Interesting as such, but no doubt the UFP is constantly inventing ways to go faster. Little of it is practical at first, as we see: not only does the UFP only gradually improve its ships, its many adversaries are similarly challenged in making significant improvements.
No doubt there are a thousand and one uses for this "new and better dilithium" that the heroes found. Harnessing it for the superdrive might take some doing, though, as the heroes never appeared to figure out how to travel at less than full throttle, or how to steer. And it's pretty difficult to see weapons applications for something you can't aim, too. This tech doesn't hold a candle to the Spore Drive.
Which the heroes do put to use - after all, it came
from the heroes. But the Borg can't be defeated with tech, since they adapt. All it gives them is a way to whup Klingon ass, such as in "Endgame" where a shuttle shrugs off two Klingon battlewagons and a tiny patrol boat then beats them to submission.
Whatever they designed to counter Species 3472
Basically just a better way to distribute Borg nanoprobes. I don't see that helping much in anything
but joint assimilation operations with the Borg...
Knowledge of fluidic space
...Certainly something to be suppressed.
Which they never could figure out, beyond the user-accessible settings. But perhaps the experts back home did better, since PIC holograms again appear improved over VOY ones which were better than early TNG ones which supposedly trumped TAS ones which appeared to trump DSC ones.
...And in PIC there is this rich Borg-scavenging industry, no doubt chiefly because of Seven and the access and insight provided by her.
All kinds of transwarp and the like knowledge
It was something of a general plot point that none of that stuff ever worked right, so the heroes didn't get home for dinner.
Starfleet had all that knowledge already: "Don't touch the stuff, yes, it has potential, and yes, it can be harnessed at risk, but no, we won't take that risk". The events of the adventure would be unlikely to convince Starfleet otherwise.
MORE proof that the Feds need to stop leaving their tech on at night lest it become sentient.
It's odd that sentient tech would not be old news already - and indeed with the EMH, we never really learn otherwise. But AI isn't exactly forbidden, nor is it exactly proliferating. Might be it's not particularly interested in expanding itself, or is capable of doing that in a way that leaves mere mortal life untouched. The EMH is unlikely to be the first hologram left running against instructions in the manual, considering how interactive holograms were a household tech in Janeway's childhood already.
Knowledge of galaxy-spanning communications networks, and how to break them. Added insight into Earth history. A few more datapoints on the Q and how to deal with it. All-new ways to treat sick Vulcans. And the whereabouts of Amelia Earhart, in case anybody is interested.
Timo Saloniemi