Yaarel
🇮🇱 🇺🇦 He-Mage
I'm not sure why you feel the need to differentiate which portions are skill based and which portions are inherent aptitudes.
Much like hp is an amalgamation of luck, skill, physical resileience, etc. In a system like the one being described your "skills" would be an amalgamation of your talents, inherent aptitudes, experience and training.
Why do I like abilities (the inherent aptitudes)?
Abilities are a simple way to provide an epitome of what a character concept is about.
For example, if a Wizard is about Intelligence and a Bard is about Charisma, it instantly communicates a large amount of information.
Races feel different because of affinities to abilities.
When I look at the statblock for a monster, I check out the abilities to know in live time how to play them.
Flavorwise, abilities are useful as a big-picture mechanic.
Mechanicswise, abilities are the engine of the D&D 5e gaming system. Everything. Everything. Everything. Refers to them. A player can think completely outside the box. No matter how surprised a DM is, the DM can think about which ability applies. Adjudicate it as an ability check. Even if a specific skill is completely absent, the ability can still apply.
Gamewise, abilities are powerful, and make D&D more open to imagination.
Why do I like FOUR abilities?
Four is a powerful number. Because of forward-backward-right-left, the foursome is probably hardwired into the neurology of the brain, and appears to be the fundamental unit of human memory, and how the brain processes information.
Four is useful.
The foursome seen in the Free League system and translating here enjoys extreme clarity. It is unambiguous which ability should apply to a specific ability check. This clarity makes the ability gaming engine more efficient, more comprehensive, and more powerful.
Narratively, the foursome coheres happily with wellknown tropes.
• Strength-Constitution ≈ Big Guy
• Dexterity-Athletics ≈ Jock Guy
• Intelligence-Perception ≈ Smart Guy
• Charisma-Wisdom ≈ Heart Guy
These four tropes relate to the Five Man Band. What makes the Five peculiar is the tendency for one of the five to be the dedicated ‘Hero’. Then, the second is ‘Lancer’ being the ‘opposite’ of the Hero, to accentuate the hero. Because of Gilgamesh and King Arthur, the Jock Guy is usually assumed to be the ‘Hero’ of the story. The Lancer, then, is his sidekick, where opposites attract. The other three are more exact. The ‘Chick’ of the Five Man Band is the Heart Guy. The Smart Guy is the Smart Guy, with various ways of being smart. The Big Guy is the Big Guy, being in some sense a one-man army who masters combat.
What makes the foursome more interesting is, there seems inherently no Hero. Any of the four can be the hero of the story, and many stories involving the foursome alternating who the center of the story is. Four is more fluid.
It is possible to arbitrarily overlay other kinds of narrative quartets (like the philosophies: Optimist, Cynic, Realist, and Apathetic).
But the narrative tropes of Big, Jock, Smart, and Heart are already a powerful tool for a storytelling game to tap into.