Now, I'm not up on all RPGs out there. I doubt there are more than a tiny few who are. Of those I do know of just one that has an integrated design philosophy. All the rest lack such a philosophy, using instead a haphazard listing the follows the original, D&D, or a variant thereupon that has about as much thinking behind it.
What thinking would that be? Very simple; what traits describe a person? In D&D those traits involve answering the following questions: How strong is he? How dexterous is he? How healthy is he? How smart is he? how wise is he? How charismatic is he? (Before somebody complains about the inclusion of wisdom along with smarts---which does come up from time to time in groups such as this, from my vantage point afforded me by my extreme age (54) I can tell you that it is possible to be dang smart, and still have the insight and empathy of a frog.)
No real attempt to integrate them, no attempt to determine how each influences the others. Health has no affect on strength, nor does wisdom influence intelligence. In real life intelligence has an impact on health. first because intelligent people tend to be healthier, and second because intelligent people take better care of their health. Then consider the affect of wisdom on charisma. The wise understand the importance of listening to other people, of taking into consideration their feelings and needs. We think better of those who take us into consideration, and deal with us as people who matter. That is what the wise do.
The sole exception doesn't integrate the parts totally into a whole, but it does come close. I won't be telling you the name of this exception, I'll leave that to your skills at research and investigation. In part because I like being mysterious, but mostly because I'd like you to consider what follows without letting your feelings regarding said RPG, pro or con, get in the way. That said, here's the scheme.
The game in question divides a man into three divisions. Three traits derived from classical Greek and Christian thinking. The classical Greeks divided Man into three parts; the mind, the body, and the soul. Such abilities as insight and understanding were attributes of the soul. Physique and agility of the body. In the game the traits are Mental, Physical, and Spiritual.
Each trait is then divided into two categories. Characteristics in D&D terms. Each serves to further delineate a character, to distinguish him from other people. The categories, in order, are:
Mental: Mnemonic; how good the character's memory is, and Reasoning; how good a person is at figuring things out.
Physical: Muscular; which rates a character's skeletal-muscular system, and Neural; which is how good a person is in matters which rely on nerve functioning. in should be noted that in this scheme a character's agility is a function of both the Muscular and Neural categories, in so far as body movement is a combination of how well developed physically a person is, and how well his nervous system functions.
Spiritual: Metaphysical; how well a person has learned to look at the world, and Pyschic; a person's innate talent at 'getting it'.
Each category is then further defined by three attributes; Capacity, Power, and Speed. Power shows how strong, how good a character is in the category in question, Speed is the measure of how swiftly how uses it. A character with a low Mnemonic Power and a high Mnemonic Speed is not all that good at remembering things, but he remembers them quickly, and can retrieve those memories that stick fast.
Capacity shows a person's potential. How good he could be if he only applied himself. If a category has a low Capacity there is not much potential there. If it has a high Capacity the character could develop Power and Speed to a high degree.
The thing to note here is that the six categories are not the same as traditional characteristics. Physical: Muscular is not strength, Physical: Neural is not dexterity. Muscular, as further defined by Power, does show how strong a person is, but at the same time when described by speed it also shows how fast one could move in stressful situations. When Muscular and Neural are added together to give a person's Physical trait we get that character's health, his constitution and endurance. It also serves as a measure of how fast the character can move when walking, running, swimming, etc. with the appropriate adjustment for the mode of movement. Basically when someone with high Mnemonic and Reasoning categories has better Mental health and endurance.
Attribute, category, and trait have further effects in the game, but such is not part of this esasy. Here I presented the basics in order to present a different way of presenting characteristics. Knowing what you now know, how would you revise the D&D scheme, or a scheme like it? What goes into defining Strength, what affects it? How would you design an integrated characteristic scheme? How many factors? How do they affect each other? In the example above body, mind, and soul are separate; how would you integrate them to give the whole man.
How is this a look at my design philosophy? That is an exercise for you to undertake. Have fun.