If a class is attractive enough then someone will play it. Obviously messing around with light sabres and force lighting is very, very attractive, and cool...but if other options are there which are just as cool, then people will go for those...

I don't think there will be one type of jedi. You can have a combat/light sabre focus, one which uses force powers more (al a mage-type character), one which can heal. (ok so I'm close to the holy-trinity there, but it does work)....

Other non-jedi classes can be just as cool. A heavy armour bounty-hunter. A quick-fast on the draw smuggler...a droid character which can modify parts...etc etc....

Make it cool make it good, and people will play.