Many will disagree with me but...as for stormtroopers, I admit the endless variations have always kinda bothered me. I personally feel like stormtroopers as seen in ANH were originally conceived as elite universal soldiers, outfitted to be able to fight anywhere, even in the vacuum of space and ranked above standard Imperial soldiers. Sure there were accessories that could be added but the base armor remained generally the same. I always though the original idea was that standard stormtrooper armor was multipurpose, adaptable and capable of being suited for any situation.
Yes, to a point. "Jack-of-all-trades and master of none is better by far than master of one." "Standard" Stormtrooper armor is (or, at least, should be -- Hero Shield and Plot Armor notwithstanding) well-suited for the wide-range of typical duty and combat situations a 'trooper will likely encounter. But...
Of course ESB comes along and they decide to introduce the so-called snowtroopers, cold weather stormtroopers. Suddenly we now have troops that seemingly have specialized armor for cold combat that fill a niche that apparently regular stormtroopers can't. Now we see that "regular" stormtrooper armor is limited in some regards and isn't so universal. However, in my own headcanon, I much prefer the notion that snowtroopers are not in fact a variant of rank and file stormtroopers but rather are Imperial Marines. For the purposes of the Hoth battle, their skirted helmets were accessorized with a heated mask and they wore winter boots for snow combat. The armor as we see it is otherwise just what they look like in any circumstance, not just cold combat. They are separate from the stormtrooper corp and thus wear totally different armor. I could buy that if it was canon...which it isn't. Then of course RoTJ introduces the scout trooper although I don't really know what they offer that a standard stormtrooper couldn't do, besides look cooler of course. Obviously their armor was heavily influence by real world motocross gear. In the real world, I'm sure the costumes were more comfortable for the actors to wear but I imagine stormtrooper armor wasn't meant to actually be awkward in canon.
Then we get to this stuff. While Stormtrooper armor is likely well insulated and efficient at maintaining internal temperature and environment under a range of conditions, for extended operations in extremely hot or cold deserts requires more-specialized kit, same with extended operations in hard vacuum (the original Spacetrooper, before it got misinterpreted to uselessness, was essentially a one-man spacecraft designed specifically to be worn/piloted by a Stormtrooper in standard armor. Got into it like a modern EVA suit and detached from the hangar wall to go do things. EVO and Magma Troopers are variants with heavier armor to deal with extremely corrosive or reductive environments. Rad Troopers are similar to standard Stormtroopers, but hardened for operations in zones of extreme radiation. These are all narrow-focus specialized gear that they're all trained to use, but to make something that is as good as all of them together would be prohibitively expensive (and maybe not even physically possible).
Some "types" are just standard Stormtroopers with a bit of extra training or kit. Incinerator Troopers, for instance, are just Stormtroopers who train with and carry around the bulky flamethrower gear.
Then there's the light infantry. Force recon. Stormtrooper Scouts are more-lightly armored because, while they might face combat, their primary MOS is scouting, outriding, and sniping. Pilots and drivers I put in this category, as well. While all are trained to fight, their main battlefield rôle is working through vehicles and other media.
When a 'trooper is elevated to Veteran status, they get the upgraded "Shadow" version of their gear. Shadow Trooper, Shadow Scout, and Shadow Guard helmets and armor are lighter, more protective, and have better electronics and other gear. Shadow Troopers often work in spec-ops, Shadow Scouts are cross-trained as commandos and demolition personnel. Above that for Stormtroopers is the gold-trimmed version, the Nova Trooper. These are, as Will Smith put it, the best of the best of the best,
sir! With honors. Bodyguards for high-ranking dignitaries, backup for Inquisitors and Hands... They're basically the Buckingham Palace Guards. People take them for granted because they're often so ceremonial -- but if a threat presents itself, hit the deck.
Besides all the variations that got introduced in the EU, the PT comes along and especially in ROTS, we see endless variations and customization of all kinds of stormtroopers (I guess called clonetroopers so we wouldn't forget they were clones?).
They are, in fact, clones who are troopers. Technically, they are Republic Troopers, a newer version of the ones in TOR. Up until Order 66 and the Declaration of Empire, whereupon they become Imperial Stormtroopers.
Even in the Disney era, we get shoretroopers (Huh? Stormtroopers dedicated to...erm...fighting on shores?) and so called swamptroopers, although I think they were actually just standard Imperial soldiers and not technically stormtroopers.
Swamp Troopers I accept as a sobriquet like "mudfoot". AKA the poor bloody infantry. They share the armor and helmet of Veers and the AT-ST crew from ROTJ. I could go down a rabbit-hole with the shared similarity to the Snowtrooper armor and helmet, but that gets murky, so I won't here.
Get ready for a context bomb, now. All those new troops we saw in Rogue One and Solo (besides the above)? ISB. That's an ISB facility on Scarif. Krennic's the Director of the ISB's technical specialist/combat engineering division, responsible for things like the
Death Star and his Death Troopers. Those tanks and cargo sledges on Jeddha were gathering kyber crystals for the
Death Star project and related endeavors. The raid in Solo was on an ISB transport. Every one of those helmet variants with that lens shape, those air vents (or whatever) flanking the annunciator... Shore Troopers are their light infantry (they may not have heavier, as they're not primarily a frontline agency, and there were a lot of standard Stormtroopers around them). Range Troopers are their Snowtrooper analogues. The tank and AT-ACT dudes are their armored-vehicle drivers. I'd say even the traffic-control dude in Solo represents a lower-priority division of the ISB -- it
is security work on an Imperial world, and that's sort of in the name. Makes me think the heavy fighter Han was testing in the deleted scene was also for the ISB, given the shared design cues of that helmet to the Patrol Trooper and Death Trooper... Even Agent Kallus in Rebels has a similar helmet (like a tank driver's, but without the faceplate and with a slightly different forehead shield).
Parallel organizations. The guys with the
steingrau uniforms are all Imperial Starfleet -- combined army/navy service. The guys with the black uniforms are Stormtroopers out of the battle armor. The guys with the light-gray uniforms with black caps are the technical branch. And the ones with the differently-cut off-white jackets and black caps are ISB. There is reason to believe there's overlap in the latter two. But they all have their own enlisted and commissioned sorts of uniforms, and they all maintain some variety of armored battle-gear.
Going on a tangent but in RoTJ to an extent, and especially in the Disney era, when stormtroopers started to be depicted being knocked unconscious by melee weapons and in some cases, armor actually being shattered(?!) by sticks, I could only shake my head. Apparently the armor literally is worthless. Disney has also seen fit to establish that apparently stormtroopers are known even in the GFFA for being bad shots (Obi-wan's comments be damned) just because our heroes had plot armor in the OT and it was something of a joke among SW fans. In the first season of The Mandalorian, Mayfeld mentions he was a sniper not a stormtrooper, as a commentary on his ability to shoot, and we actually see two scouts trying to shoot a target at near pointblank range and still missing, to comic effect. With the way they are depicted, especially now, I can't imagine why they were ever feared or effective.
This part, I am right there with you. I am baffled by the people who still don't get the Stormtroopers on the
Death Star were missing ON PURPOSE! The rest of the time, we've seen them being super-effective. Even the ground battle in ROTJ was seeing a LOT of Ewok casualties and collateral damage to the forest. Even if the armor protected them from serious injury, all that was needed was for a trooper to be knocked off-balance long enough to be swarmed under with stabby little bastards. I'm curious if Marine Snipers sneer at the "merely-competent" Riflemen... But yeah, I hate all recent depictions of Stormtroopers being bumbling comic relief. I
do like them when they're effective, though.
