Let me take a different stab at this.
If you were statting up James Bond for d20, would you give him a 10 Cha and no ranks in diplomacy or intimidate? Why or why not?
If you were statting up Einstein for d20, would you give him a 10 Int? Why or why not?
If you were statting up Stephen Hawkins for d20 (since he just came up here) would you give him an 18 Con? Why or why not?
Now, if you answered no to all those above, then obviously you believe that stats matter. I'd love to see the justifications for those who tell me that stats don't matter telling me that yes, it's perfectly acceptable for James Bond to have a 10 Cha and no ranks in Diplomacy or Intimidate.
This should be interesting.
This is a good question, sort of the inverse direction I've put things.
Bear in mind, I've been advocating a hypocritical position. I do play my lower CHA PCs differently than my high CHA PCs.
If I was making a Bond style PC, I would probably give him better than average CHA. I might not put an 18 in it.
But I also accept that somebody else might make an 8 CHA PC that acts like Bond. The difference is, every pick-up line will require a skill check and that'll mean he likely fail and come across as cheesy/sleazy, rather than suave and debonair like Bond.
For me, the skill system takes care of the charisma mis-match problem. Just roll checks on everything. In fact, these threads may have convinced me to not give circumstantial bonuses for well-spoken speeches, so as to not artificially inflate the PCs skill from the player's.
For GMs who like to encourage role playing (and thus speaking/acting in character), giving out an XP bonus might be better practice than giving out a skill check bonus. If you act "in character" during an encounter, get some extra XP. But you can't player-charisma-tize the encounter to success where your PC-charisma would fail.
A reason for that, as I think [MENTION=2209]Voadam[/MENTION] said in one of these threads, is that of 2 low CHA PCs, a player who correctly RP's his PC as a jerk would get his base CHA penalty on the check AND the GM would naturally interpret things against him (or apply a situational performance penalty). Whereas the player who only rolled, never roleplayed would just get the CHA modifer, and never have a performance penalty applied.
There would be a perverse effect, where "correctly" role-playing your PC as low CHA would result in more failures and problems, than just roll-playing your PC with the same low CHA. That's a disincentive to role-play (to play in character).