B/X Known World
Fighter, caster, rogue (aka skills expert). Everything in 5E fits one or more of those three or is a reskin of those. There’s a huge difference between the skin and the mechanics. I’m talking about the mechanics.I don't think parent classes are bad. However I don't think all the common expanded archetype in Modern D&D can fit into 3 or 4 parent classes without glut and bloat.
Monks, alchemists, tinkers, beastmasters, tacticians, scholars, jaguars, and artificers don't fit the fighter/caster/thief nor fighter/priest/mage/thief without extremely tilting the parent class and forming child and grandchild subclasses.
The "Everyone fits into these 3/4 archetypes" only works if you limit the typesof characters to very old school settings.
There’s 13 classes. Fighter, wizard, rogue are the base three. So that leaves ten. Artificer is a caster/skills expert. Barbarian is a fighter without armor. Bard is a caster/skills expert. Cleric is a caster with a little fighter for the arms and armor. Druid is a nature-based caster. Monk is a fighter/skills expert without armor. Paladin is a fighter with a little bit of caster for the smites. Ranger is a nature-based fighter/skills expert. Sorcerer and warlock are casters with funky mechanics.
For an example of skin, look at the rogue and the ranger. They’re nearly identical, the only difference is one plies their trade in the cities and towns while the other does so in the wilds between them. What’s the skin difference between a tinkerer and an alchemist? Which tools they focus on and how what they produce is described. The 13 classes in the game, even with the subclasses, aren’t really that wide ranging and diverse.