Kudos to Ion Raven for an interesting thread.
Mechanistically speaking, Shalelu is no surprise... charisma is the least useful stats for most rangers, unless they are heavily into animal companions.
As to the OP concept: This is quite interesting, but you are right. Certain personality types would be associated with a low charisma. And many people may be attracted to those types of personalities. High charisma, as I see it, would be an advantage as a first impression, but would vanish in the long run.
Take the excellent example given by Jiggy above, of his cha 8 character who's focused, pragmatic and driven, with little time for niceties. (the typical rpg good-aligned ranger, in my opinion)
The sorceress in the first post may at first be more drawn to a silver-tongued cha 16 bard. But after getting to know both of them, she may begin to admire the cha 8 warrior for his personality traits.
Of course, if she doesn't take the time to talk to him (or if the warrior does not make the effort to press his suit) she would not realize he has those traits.