Nearly all the wizards I've ever played have had decent-to-high CHA. Reason being, a lot of the spells I like involve CHA Checks (for Charm Person/Monster [or Dream Casting "Charm" if you can't cast Enchantments], Planar Binding series, Command Undead, etc.). Plus, "Social Wizards" are fun. And there's a mindboggling array of terrific social skill boosting spells for a wizard in both 3.5 and PF. Of course, there's the UMD-boosting advantage as well too. I need to look more at PF traits, but I believe there might be a trait out there that converts all the Knowledge skills to CHA based instead INT based. Which for a Charisma Wizard like the one you are looking for ... would be all sorts of awesome.
Plus, a wizard who can get maximized benefit with the typically sorceror-dominated spell, Ruin Delver's Fortune, is just tons of ace when it comes to immediate-action defensive goodness.