The biggie that keeps getting overlooked is in the defenses and pre-run usefulness.
Plenty of spells are defended using Logic. All your wireless items are, too - do you want to be That Guy who let the corporate security crack their commlink so they could overhear all the plans?
Charisma is good for facework and drain, certainly, but that shaman is also going to be the one who reveals your locations to security when they mark his commlink and trace his location, then is the one to fireball the rest of you when the wagemage takes over his feeble and puny illogical mind. Not to mention how useless they are when it comes time for non-face legwork with their low low knowledge skills and low arcana. "Hey shaman, what do you know that could help us out?" "Uh, I like the Earth?" "Wow, super useful! Hey mage, you got anything?" "I'm basically a walking encyclopedia when it comes to absolutely everything that could ever involve magic." "Well how about that, a thing we can use!"
In my experience, to add to this, shaman tend to put all their eggs in one basket - yeah, charisma goes sky high, but will lags behind a bit. Hermetics on the other hand I notice tend to go more equal on will and logic and end up with better defenses all around. It also gives dwarves a decent niche.