Pets!
#6 The Diplomat or Politician (Galactic Republic)
The Diplomat brings to mind such characters as Chancellor Palpatine, Padme Amidala, and especially Leia Organa, but why the heck is this a pet class?
The answer is easy, bodyguards. It is pretty commonplace for diplomats or politicians to have bodyguards, so the class would draw most of its combat abilities from their pets. The diplomat would perhaps be allowed more choice in companion characters, more companion characters than would be normally allowed, etc. To use Queen Amidala as an example, you might even see special pets in the form of decoys, trading some combat capability in order to confuse your foes.
The diplomat would also be helpful in groups. For example, it has been revealed that BioWare has essentially made dialogue multiplayer in The Old Republic. While that is its own can of worms (Kill him! No, spare him!), it also provides some interesting possibilities. A diplomat would be handy in group situations to perhaps help a friend get out of a sticky situation in a quest dialogue event, or gain access to information that would otherwise be unavailable, etc.
#5 Crime Lord (Sith Empire)
This is the Sith Empire's answer to the Diplomat; this class would be largely the same, though perhaps more focused on offense and underhanded techniques. Domination or bribery dialogue options, bribing (charming) NPC enemies, perhaps even turning a diplomat or other players' companions on their masters, are potential abilities of the Crime Lord. Think of the Mastermind in City of Villains, or you know, Jabba the Hutt. Just having Hutts playable would make my day, I mean come on, who doesn't want to make a Hutt named Pizza the Hutt? Ah, but I digress.
#4 Droid Engineer (Sith Empire / Galactic Republic)
Droids are loved by many Star Wars fans and there are many gamers who appreciate all things mechanical, so naturally some sort of droid engineer would be a clear fit. The droid engineer would make use of powerful droids in and outside of combat. How about an army of HK droids at your disposal to put the fear of God into those damned meatbags? Or maybe, even some medical droids to assist in healing your allies? The possibilities are pretty deep. Droids also have a wide representation within the films and Expanded Universe filling a multitude of roles from Protocol droids like C-3PO to well, being useless, like MSE-6 Mouse Droids (ok, they're cute, but what do they DO?!). Consider this class or a class like it pretty likely.
Stealth
#3 Imperial Intelligence Agent / Sith Spy (Sith Empire)
Some people are divided on whether the Bounty Hunter is the "mirror" of the Smuggler, or whether the Bounty Hunter "mirrors" the Trooper. If you subscribe to the latter theory, then there is a hole, at least right now, where a mirror to the Smuggler is concerned. I did mention the Sith Assassin as a potential option, but there is also the Imperial Intelligence agent or Sith Spy to consider. A recent thread on the official Star Wars: The Old Republic forums lends some credibility to this theory. Many fans, including myself, were confused to see what appeared to be a Smuggler in the Deceived trailer shown at E3, assisting the Sith against the Galactic Republic. After all, the Smuggler is a Republic class. What gives? The thread in question shows an early screenshot from The Old Republic of a character in a uniform that closely resembles that of the Twi'lek in the trailer, making use of the cover system and wielding a pistol. While it could be considered somewhat of a stretch, the possibility of a Sith Spy is there.
Wish List / Honorable Mentions:
#2 Pilot (Sith Empire / Galactic Republic)
No one knows whether Star Wars: The Old Republic will launch with space gameplay, but if it did, what about a pilot class? Fans of the old LucasArts space games such as X-Wing vs. TIE Fighter, X-Wing Alliance, or even Rogue Squadron would be in heaven (I know I would) if the game included space gameplay with a storyline as deep as what we can expect from the other classes. The problem, of course, is what would they do on the ground? Call in air strikes? It's hard to say. Though there is an argument to be made for this as an "iconic" class. After all, Luke spent a large portion of his adventure as a pilot in the films before he really came into his own as a Jedi. This class is much less likely, though something I would personally be excited for were it announced.
#1 Slicer (Sith Empire / Galactic Republic)
Fans of the Expanded Universe would love to see a slicer in The Old Republic. The best real world comparison to a slicer would be a hacker, or more appropriately, the Hollywood version of hackers. Slicers often lived double lives, having different identities and selling information. Armed with a datapad and technical know-how, a slicer can get you the information you need, or into areas otherwise inaccessible.
Most examples of slicers are found in the Expanded Universe, but they received a subtle mention from Mon Mothma in Return of the Jedi with the line "Many Bothans died to bring us this information." Bothan spies are notorious for being excellent slicers. This class would be a sure fan favorite if announced for The Old Republic.
Unfortunately, there aren't too many practical applications for a slicer's skills in your everyday combat situation, so I don't see this as a likely class to appear in the game. Perhaps, like Smugglers in Star Wars Galaxies, the gameplay options will be available through a feat tree, but hopefully unlike Star Wars Galaxies, that slicer gameplay won't amount ridiculously "slicing" gear to upgrade for players. Slicer gameplay would make excellent sense for a Sith Spy / Imperial Intelligence Agent as well. At the very least, expect slicer companions. Atton Rand, a companion character in Knights of the Old Republic II was also a slicer.
That about wraps it up for our list of potential Star Wars: The Old Republic classes. Got your own ideas for potential classes? Let us know in the forums!