Look I agree that having non-jedi classes would be better, if they worked (tho I think you can imagine some problems that would arrise from that. A regular Gijoe guy blasting away dark jedi left and right seems as bad as having lightsabers that can't cut through anything. Not to meantion that you then lose the whole "force alignment" angle of the game. Which I imagine might make it harder to craft a story to fit all possible characters.). I really think the choice to force the player into the role of a jedi is due to the choice to make the LS/DS and NPCs systems (seemingly) deeper and more meaningful.
As for jedi being the same: The three classes arn't so different than having a Magic User/ Intermidiate/ Warrior.
As for not using a lightsaber/force: The player will always have some level of useful force powers to use, I agree. It doesn't mean, via the player choices, that a lightsaber is the only viable path for the player. It's like saying you should have been a combat boy in FO because that was the easiest way to beat the game.