For a real life example of a fighting man that had many other skills, consider the Roman Legionnaire. Pretty much defines the basic D&D fighter. Sword, shield, armor, helmet. Kills things. Pillages the result. But when the legion wasn't fighting, it was the empire's engineering corp. Building roads, bridges, buildings, aqueducts, etc. Lots of non fighting skills there. Plus exploration, freight moving, and managing far flung provinces. More non fighting skills.
That's similar to the sort of thing that led to my thinking. There are a ton of (non-spellcasting) fighter heroes in fiction that clearly don't fit into the "Thief/Rogue" archetype. But they are still good at things like sneaking, scouting, and the like. If the Ranger
has to be a spellcaster, then the fighter has to be expanded enough to cover the skirmisher character as well as the frontline combatant. If the Barbarian is built around Rage, then Fighter
has to cover characters like Conan and Fafhrd, although one could work in a little Rogue/Thief as well.
Similarly, "Swashbuckler" is as much a Fighter-archetype as it is a Rogue one. Madmartigan? He, too, may be multi-classed, but the "greatest swordsman who ever lived" had better be primarily a fighter, or the class is silly.
Even Aragorn is primarily
not a spellcaster, doesn't wear armor except for battles, and mostly (exclusively in the books) fights with a sword, not a bow. In the movies, he has a short hunting bow that he can (and does) use in battles, but it's a secondary weapon for him. But yeah, he's skilled in wilderness lore, can move stealthily, and is a learned figure, but why does any of that make him "not a fighter?"
I think one way D&D lost its way was basing most of the Fighter's abilities on either STR or CON. Plus several editions of encouraging min/max character builds. PF1 didn't really change this. If a Fighter needs INT to spot the weak points in an opponent's armor, then all of a sudden, Fighters will start having extra skill points based on a higher INT. Or maybe create a feat/trait/background feature that lets a character use the INT bonus to hit instead of STR or DEX(*). The smarter character is better at seeing an opponent's weak spots.
* there may be one, hard to keep track of hundreds of feats scattered across many books.
I think D&D lost its way in the start by asserting that STR is the basis for melee combat. While arguments can be made for bludgeons, axes, polearms and the like being STR-based, the ability to use swords and spears effectively is primarily
not based on strength, but rather on agility (DEX in D&D terms). Because D&D lumps armor and defense into one category, an argument can be made for that (a heavy enough blow can pierce armor), but that really isn't how swords work. Swinging harder not only doesn't help with accuracy, it actively hurts.
Short version: 5e has made progress by putting all the classes on a more even keel as regards proficiencies, but I wonder if some of the reasons they've had trouble making the Ranger class compelling (can't have the Ranger tread on the fighter's toes) is that a lot of the canonical characters we think of as "Rangers," like Lan, Robin Hood, Legolas, or Aragorn(*) should just be fighters. There's nothing like D&D spellcasting in their worlds, so the D&D "Ranger" doesn't fit.
(*) Aragorn is a special case, because clearly the D&D Ranger was sort of modeled after him, but there's a very legitimate argument to be made that Aragorn is better represented by the OG AD&D Paladin. He can cure wounds, especially the Black Breath (Athelas is a material component), has some ability to rebuke the undead, carries an heirloom sword, and has a special bond with a horse (Roheryn in the books). But really, he's just a fighter who's also stealthy, charismatic, and learned, and all his vaguely supernatural abilities are a result of his heritage (and age), not his occupation.
