If you look at the weapons posited in the 1977 version of Traveller they were basically 1977 weapons that were bigger; Lasers (well documented in 1977) and the dread PGMP (also pretty well documented) - while low-tech plasma weapons using explosives were in existence from the 1930s, they aren't seen much in Traveller.
The concept of remote drones didn't feature at all at any tech level.
But the higher tech levels add a lot of new basic technologies that may transform warfare
Computers that know where they are and communicate with other computers that know where they are make LOS nets possible so a pair of binoculars become a 3-d view of a battlefield from the scatter of tiny drones
The same for broadcast nets but with earlier application
EW become a major issue as all those nets are critical. Personal EW systems seem likely. PD systems are vital to kill those homing drone swarms. Using a radio or laser is suddenly very dangerous as those homing weapons are now intelligent and loitering.
Tazers didn't exist in 1977. Taser rounds for shotguns and bean-bag rounds didn't either. Nor ceramic rounds that don't penetrate hulls but are nasty for unarmoured crews.
Bio-engineered insect swarms or micro-drones - how do you get past that personal PD?
Nano-tech has to overcome the fact that biology has been dealing with small bits that get into blood for millions of years and are quite good at containing them.
Densitometers are big bits of kit, but make seeing through things possible
Dopler systems that detect the motion of blood in a person
High-Tesla magnetics can float frogs. What could that do to a fusion drive or person with a bit of imagination?
Nuclear Dampers muck up strong force. OK, they become disintegrators at TL-16 but what else could they do at lower tech levels. Lots of low energy neutrons escaping from normally stable nuclei can really change the half-life of materials.
Dark matter didn't really (actually?) exist as a sci-fi concept in 1977. As people can manipulate gravity, what does that allow when applied to dark matter?
Mines using grav plates could do odd things to grav-vehicles.
Gravitic laser focussing suggests that you have g-fields well over 10G! That makes particle accelerators perfectly possible heavy weapons.
Quantum weaponry wasn't a concept in 1977 (unless you include psionics). Where does that lead you? By the early 1980s there were meson cannon in Traveller. Any other odd quark constructions that might be usable?
"War amongst the people" was practically ignored by Traveller. What does that concept do when mixed with those high-tech systems? It doesn't bode well when a small "Maker" starts turning out viruses and bacteria in their thousands of trillions.
I'm fairly sure Polonium wasn't the concept in 1977 it is now seen as. Bio-weapons were so scary in 1977 that they were banned...and (even now) we have much better technology now for making and combatting them.
And the world of cyber-punk has never really hit Traveller despite the tech needed to make it work being extensively available on many worlds.
The full effects of the "Agent" tech are really under-estimated and with money and power would have a potentially nasty military usage...All the enemy combatants suddenly have the urge to change sides because their minds have been warped? Psi-Ops on steroids!
"Tazers did not exist in 1977"...
No. But stunners are pretty much the same thing (for effect) and they'd been available in Science Fiction for a generation or two. And I seem to recall them being available in Traveller in the black box set.
"Nuclear Dampers muck up strong force. OK, they become disintegrators at TL-16 but what else could they do at lower tech levels. Lots of low energy neutrons escaping from normally stable nuclei can really change the half-life of materials."|
Actually, I'd think nuclear "damper" fields must be increasing the strong force ("slightly...") to be stopping nuclear explosions. The neutrons &c. can't get into the nucleus to disrupt it. The inverse (decreasing the strong force) would be a disintegrator.
Messing with "dark matter" using gravity fields probably wouldn't make much difference to the universe in general until you get up into at least the thousands of Gs. Dark matter as we "understand" it now doesn't become a problem until it starts condensing into black hole-ish densities.
"High-Tesla magnetics can float frogs..."
And literally turn on/off sections of your brain and trigger/suppress memories, per modern PET scan research. Maybe make you forget how to breath? Your heart forget how to beat?
Of course, a bullet can do the same thing, only faster and cheaper.
"The full effects of the "Agent" tech ..."
...were envisioned long before Traveller, but how much fun is that to play?