This apparently was a conscious decision on the game designer's part: they didn't want appearance to be conflated with Charisma any longer, but neither did they want to rate it separately, as Gary did in Unearthed Arcana.
Yeah, pretty much since 3rd Ed. came out, there was a lot of discussion on the different forums, including WotC's own and among several of the designers themselves, about downplaying the importance of physical attractiveness aspect of the character's CHA score.
Personally, before 3rd Ed. became the primary ed. that folks around here played, I encountered several DM's with some seriously "questionable" ideas about Charisma.