Adventures in Aduelle: Primordial Aptitudes

So I've made a little more progress on Adventures in Aduelle, and I've got a little bit of stuff to show for it; here's a quick excerpt of the current "Aptitude" system, which basically functions akin to a general category of characters' abilities.
In Adventures in Aduelle, characters are rated by four Aptitudes, taken from an ancient mystic tradition pre-dating the Shattering, one of the few traditions to escape total destruction but one which still remains a mystery to even the most skilled scholars.
The Primordial Tradition, or at least the inscriptions that remain, detail four essences of each individual- their Flesh, Persona, Mind, and Ghost.
Flesh is a measurement of size, toughness, and strength, and people with a high aptitude for Flesh are capable of lifting massive weights and shrugging off wounds that would kill lesser mortals.
Persona is a measurement of how a person appears to others and how they consider the world around them; someone with a high aptitude for Persona would be capable of talking to others and would also be considered to have good common sense and reasoning. Persona is also used to gain Ascendants' intervention and use some magical traditions.
Mind is a measurement of mental acuity and calculations; people with a high aptitude for Mind are known to be capable of using most forms of magic easily, as well as being capable of functioning as craftsmen and being perceptive.
Ghost is a measurement of how a person can move; it is more than just nimbleness but it tends to manifest as such: stealth, acrobatics, and some forms of magic rely upon a person's aptitude for Ghost to determine their effectiveness.
I don't really have a full-fledged final idea of how the mechanisms work, but the way the game works is 2d8+16 against a target number (the +16 gets lowered on account of penalties and serves as a way to make a totally bruised, battered, and near-death character near incapable of doing anything of even moderate difficulty to a novice adventurer) with the ability to add up to four points in modifiers (from each category) through equipment/magical buffs/whatnot, skills, your Aptitude, and an attribute that governs skills.
Four is sort of a hard cap on advancement, and represents a level of power equivalent to a level 15 or so Dungeons and Dragons character. Aptitudes will often start at this level (the players take on the role of heroes, after all), but other stuff will start at level one or two if it even can be had at the beginning.
The way I'm thinking Aptitudes will work is as follows:
Each character starts with two points in each of their aptitudes, and adds on one aptitude point for each of their nation of origin's favored attributes. They may also add on two additional aptitude points, allowing them to either have three points in each of their aptitudes or have one or two aptitudes have four points. Aptitudes cannot exceed a rating of four points.
Attributes cannot exceed a character's appropriate Aptitude unless they have a special reason to exceed them (a temporary buff, trait, or blessing). By extension, because Skills cannot exceed their linked Attribute's rating, the Aptitude serves both as a general bonus to a wide array of skills and a limit to their growth at the same time.
Aptitudes are not capable of being improved like a normal attribute or skill; powerful magic or divine intervention can improve them but this will require a heroic act (basically if you make it through several scenarios you might get an aptitude increase). The ratings required to improve an aptitude fall outside the realms of normal player achievement, involving ratings of 8 or so in the appropriate aptitudes, attributes, and skills on the character who is using a magical method (which can boost only to 4), or requiring the direct intervention of an Ascendant, Outsider, or Jutil himself (which can boost up to 8, which is Outsider-leveled power or roughly the equivalent of a superhero on steroids).
In Adventures in Aduelle, characters are rated by four Aptitudes, taken from an ancient mystic tradition pre-dating the Shattering, one of the few traditions to escape total destruction but one which still remains a mystery to even the most skilled scholars.
The Primordial Tradition, or at least the inscriptions that remain, detail four essences of each individual- their Flesh, Persona, Mind, and Ghost.
Flesh is a measurement of size, toughness, and strength, and people with a high aptitude for Flesh are capable of lifting massive weights and shrugging off wounds that would kill lesser mortals.
Persona is a measurement of how a person appears to others and how they consider the world around them; someone with a high aptitude for Persona would be capable of talking to others and would also be considered to have good common sense and reasoning. Persona is also used to gain Ascendants' intervention and use some magical traditions.
Mind is a measurement of mental acuity and calculations; people with a high aptitude for Mind are known to be capable of using most forms of magic easily, as well as being capable of functioning as craftsmen and being perceptive.
Ghost is a measurement of how a person can move; it is more than just nimbleness but it tends to manifest as such: stealth, acrobatics, and some forms of magic rely upon a person's aptitude for Ghost to determine their effectiveness.
I don't really have a full-fledged final idea of how the mechanisms work, but the way the game works is 2d8+16 against a target number (the +16 gets lowered on account of penalties and serves as a way to make a totally bruised, battered, and near-death character near incapable of doing anything of even moderate difficulty to a novice adventurer) with the ability to add up to four points in modifiers (from each category) through equipment/magical buffs/whatnot, skills, your Aptitude, and an attribute that governs skills.
Four is sort of a hard cap on advancement, and represents a level of power equivalent to a level 15 or so Dungeons and Dragons character. Aptitudes will often start at this level (the players take on the role of heroes, after all), but other stuff will start at level one or two if it even can be had at the beginning.
The way I'm thinking Aptitudes will work is as follows:
Each character starts with two points in each of their aptitudes, and adds on one aptitude point for each of their nation of origin's favored attributes. They may also add on two additional aptitude points, allowing them to either have three points in each of their aptitudes or have one or two aptitudes have four points. Aptitudes cannot exceed a rating of four points.
Attributes cannot exceed a character's appropriate Aptitude unless they have a special reason to exceed them (a temporary buff, trait, or blessing). By extension, because Skills cannot exceed their linked Attribute's rating, the Aptitude serves both as a general bonus to a wide array of skills and a limit to their growth at the same time.
Aptitudes are not capable of being improved like a normal attribute or skill; powerful magic or divine intervention can improve them but this will require a heroic act (basically if you make it through several scenarios you might get an aptitude increase). The ratings required to improve an aptitude fall outside the realms of normal player achievement, involving ratings of 8 or so in the appropriate aptitudes, attributes, and skills on the character who is using a magical method (which can boost only to 4), or requiring the direct intervention of an Ascendant, Outsider, or Jutil himself (which can boost up to 8, which is Outsider-leveled power or roughly the equivalent of a superhero on steroids).