New lvl cap: 70
3 new planets for lvl 55-70: Dantooine, and I don't know enough side lore to pick the other 2, Dxun might fun.
1 new starter "planet" for new class: Asteroid Outpost Jedith
2 new classes: Jedith rogue, and Jedith combatant
The new classes focus around the Jedith amalgamation. A group of force sensitives who train together but are outside the Sith and the Jedi, they don't belive in the strict rules of the Jedi, or the hatred of the Sith, but they don't hate the other orders. However the Jedi want their order disbanded as they don't believe that you can have an order without their rules and not lead to the darkside. The Sith see them as an opportunity, the Jedi discover Jedith at the end of the 3rd chapter, and become distracted from the war effort, allowing the empire to make it's comeback. The Jedith are led by a very powerful Jawa named Jeebii. Though the Sith don't approve of the Jedith order per say, they are useful for now, and some of the Sith, such as Darth Marr believe that they may be the key to winning the war (and will accept them as permanent allies). seeing as the Sith aren't trying to destroy them, the Jedith are more ready to side with the Sith if they are forced to take sides. The Jedith train force sensitives to be able to use their abilities and give them a safe haven and a place to teach if it behooves their members. Other than that after training you're free to live your life, meaning that after you play through your tutorial you get to pick to either join the republic side or the empire. Jedith training focuses on not only using the classic force user powers but also on the use of conventional weaponry. Jedith rogues are armed with both a lightsaber and a pistol and choose between swashbuckler (dps, focuses on combat) and trickster (heal/tank, focuses on tech and force powers). Jedith combatants fight with all new weapons such as the light fist (essentially lightsaber brass knuckles) if they chose the pugilist advanced class (dps/tank, who dives into the fight) or lightwhips (lightsaber whips) if they chose the renegade advanced class (dps/stealth who practices tactical combat).
All classes would receive a new unique companion
All romancable companions would be made bisexual (and subsequently all conversations with said companions would reset as to not screw over people who have already completed)
New species: Android (would be so high tech it functions just like organic characters, with a few unique lines of dialogue but all the options of an organic character)
Republic classes trooper and smuggler would get the option to betray the republic and join the empire
New Warzone: Battleground Alpha- basic warzone, periodic air strikes and enemy npc soldiers all around devastated city, patrolling tanks, various locations you can take control of which give boosts to your teams bonuses.
New Operation: I haven't played all of these yet so I don't know what it would be.
Republic classes plot lines:
Jedi knight: Would be sent on the questionable quest of building up to eradicate the Jedith.
Jedi councilor: Would be gathering information on the Jedith.
Trooper: tries to keep in the war but gets dragged into the Jedith situation as that's where most of the fighting is happening now
Smuggler: Tries to keep the Jedi order away from the Jediths throat (an old partner you owe a favor to turns out to be a Jedith), while making some credits along the way.
Imperial Classes plot lines:
Sith Warrior: Gets the job of trying to decimate all republic/Jedi forces that set up to battle the Jedith or the Imperial forces.
Sith Inquisitor: searches for anything the empire can use to fight the war.
Imperial agent: assigned with the old group from imperial intelligence to defend the Jedith and get them to ally with the empire.
Bounty Hunter: hired by the empire to hunt down significant republic/Jedi heads.
Jedith history has them being founded after the Mandalorian wars, a clan that was setting up an ambush on an asteroid belt after hearing about Malacor holed up there and decided that the force obviously wasn't like they had thought, and begun practicing it themselves. They were trained by a single Jedi who had betrayed the republic during the wars to join the Mandalorians when he decided that they would make better leaders of the galaxy. Since then they have simply existed, training anyone they can recruit, and staying hidden, they have produced many bounty hunters and mercenaries who the republic has always counted off as isolated incidents. Jeedii took command recently when his predecessor died of natural causes. Jeedii was a Jawa shaman in training who's tribe was destroyed by sand people, and was taken into the Jedith, since the neither the Jedi nor the Sith thought that Jawas were force sensitive.
If I forgot anything please let me know
EDIT: I forgot, it would also enable you to customize your ship.