OK
how about you start as a student of the new jedi acadomy. You can choose to stay or go to a re-built korribian, and spend some of the game there.
WHere you go influences which side of the force you learn. After some time, and quite a few different sub-missions and missions, you go on a mission to coruscont, where you meet a strange elderly lady who warns you to go to certain galactic co-ordinates. When you get there you infultrate a true-sith base and find reven and the exile. You can have both come with you. You all do alot of damage before finding a true-sith plot to attack the galaxy, or something similar.
Basically you return to the galaxy. You can go to all of the planets from 1 and 2, with more. You meet all of your allies from 1 and 2 asking for help, and go to some more new ones. For each of them you must solve problems of theirs before they help you.
At the end there is a massive battle against the true-sith.
You have mandalorians, jedi, a few sith, soldiers from most planets and multiple heroes with you.
I think loads of your guys should die