IMO there isn't necessarily a need for more classes. Instead, there should be customization options and expansion to the standard six classes. There should be multiple model options for classes (Jedi could have their whole apparel changed, but the other classes should at least have two or three different models to choose from). Also, weapons and items should be allotted to a class through a point system much like the force power configuration in MP. All classes would obviously be restricted in their choices, but they could have the option to use points for available items such as sentry turrets and bacta tanks to weapons like the E-11 or TDs. More ammo could also be "bought" with points. This would make Siege much more interesting.
Hopin' LEC is going to get on track and bring us a decent JK for the JKers of 1997.