Lt. Ambrose said:
A Halo MMORPG would probably be best constructed like Star Wars Galaxy originally was. Everyone chooses from a few classes, like Soldier or whatever. You play and play and play and eventually, one day, get to choose to switch to the Spartan class....Of course, instead of getting to choose it at a certain level, I'd say the best choice would be for game moderators to pick players at random within a certain area of levels....So not EVERYONE would get to be a spartan just by spending hours of grinding and leveling up. Essentially, the Spartan class would only be available to the Elite.
From what I understand, this is sort of how people attained the Jedi class in Star Wars Galaxy, minus the 'being randomly picked' part. So yeah.