I heard on one of the more recent videos about the game (from the commentator not a larian employee) that Larian is thinking of disengaging the dialogue skills (charm, intimidate, etc) from the main stats.
If that true then why not tie them to the character's personality stats? The ones that go up or down depending on dialogue choices. Those character personality stats will affect party morale and traits as far as we know but I think it would be interesting to have them affect dialogue skill rolls as well. You raise them by having dialogues and they could in turn affect dialogue skills. Not to mention it makes more sense for someone who is calculating and realistic to be able to win a reason check than just someone who has high intelligence or someone ruthless and self serving could be more intimidating than a character that is just strong.
The most interesting thing about having such a system is that it is dynamic. Your characters' opinions shape their character and in turn their character influences the way they behave. Even in real life is someone tries to act out of character, unless he has really good social skills (perhaps a trait?) it would come out as akward. Larian has announced that dialogue skill checks will be influenced by the context of the situation. Having them influenced by the character of the player would be, in my opinion, a good attendum to that.
