Jason said the archanist was a wizard/sorcerer mix. It had a spell book but when you prepared spells, each spell had 'slots". He then summed it up as a sorcerer that basically could change there spells but could cast less a day than a normal sorcerer.
He also said each of the classes will have a unique mechanic. The swashbuckler doesn't have grit but one called bravado (if i remember) instead.
A question i forgot to ask him was if there are new favored class options for each race for these new classes.