Edit @ Garile: I never said it is impossible to RP max STR stat. I said that
was possible.

@Prolix
The faction system will deal with how NPCs react to you. That makes charisma a redundant system that is not needed.
As for the rest, nothing you have written addresses that fact that a player is not forced to play to others' or their own charisma or intelligence stats. Your examples are inane, extreme, and prove nothing. You do not address the character that has low charisma stat because of the lameness of Creation, yet the player can convince a tavern full of people to do something they would normally not. You do not address the character with an average charisma, yet the annoying player is avoided by people who would normally go along with what he is suggesting. Even your 'max' example is lame and full of "Well maybe" and "what if" so that you can avoid using the charisma stat if you don't want to.
"Well maybe my character does not like your smile, then I can ignore your high CHA stat, and decide not to go to the tavern with you, even though I was about to go there anyways."
"What if I am drunk, so the character seems to have more charisma than their stats say they do? Then your low CHA character can easily convince me to go to the arena."
You are modifying your own character's 'reality' to adapt to your abnormal reaction to other character's so-called charisma stat. Some would call that godmoding.
You also resort to the age old (and very lame) argument that if someone wants one stat removed, you might as well take them ALL out. That is the childish 'all or none' argument, and does not float any kind of boat.
So, your character has a high charisma stat. What exactly is that? Is he dark and imposing? Is he the intelligent, powerful speaker? Is he jovial and endearing? Is he the wisecracking funny guy? Is he suave and charming?Is he crazy and fun (you know him as the guy who can convince anyone to do crazy things just for fun)? Is he huge and intimidating? Is he solemn and serious? Is he the wormy guy with the magic tongue? Is he a combination of the above? CHA is not useful as it is intended, as it does not even define what it is. Zak would react positively to the 'dark and imposing' charisma, but would gut the 'jovial and endearing'. Jayose would find the 'wisecracking funny guy' to be a mud-dobber, while would find himself drawn to the 'intelligent, powerful speaker'.
Charisma is a terrible catchall, as it refers to many completely different aspects of a personality, and what can make one person seem charismatic to another.
Back to magic.
Is the Suave and Charming guy going to be able to cast 'charisma' based spells in the same way the Dark and Imposing guy will, if they have the same 'charisma level'. What of the Huge and Intimidating? Is he a magical match for the Wormy Guy with the magic tongue? Which of all the above is going to be able to magically charm a raging trepor the best?
If charisma is how others perceive your character, is it others that govern how powerful your spell is? If you start acting like an uncharismatic, jerk, is that going to reduce your CHA-based magical powers? How exactly does CHA affect magic in the first place? Does your charm (only in the case of a charming person) draw more mana to you? How about the imposingly dark and charismatic guy or Crazy and Fun guy?? What effect do those have on making his spells more powerful?
When you can answer all of the above with one satisfactory, all-encompassing answer, I will bow my head and admit you are right.