Type vs Class
Including droids -- a pretty much inorganic bunch -- as a character type option has consequently changed the way GSW PCs will develop over time.
In D&D your character's Hit Dice and Saving Throws are tied to his class. As he gains XP and moves up levels his Hit Point pool grows and his saves get better according to his profession.
GSW will deviate from this practice. As your character increases in level, his Hit Dice and Saving Throws will change according to his Type ["Race" in D&D terms]. Thus a 7th level Twi'lek Bounty Hunter will have the same Saving Throws as a 7th level Twi'lek Sith warrior and their HP totals will share a specific range.
Fighting ability and a host of profession-specific abilities [a few for each class] will still be tied to character class and will develop according to class descriptions. And class will ultimately still play a role when it comes to HP and saves because different classes require different XP totals to advance from level to level.
I think this will create some interesting advantages and disadvantages to playing certain types. For instance, Droids will have a static number of HD that will only change through some in-game modification. In other words, 1st level Droids will start the game with more HP than other types, but they will not aggregate more Hit Points as they gain levels in the manner of the organic types.