Greetings!

With the Legacy tree, I think it would be pretty cool to pit your characters against eachother indirectly. For instance, my Marauder is my Shadows rival. To make that play a larger role with my characters, it would be pretty cool if my marauder could send one of his companions on a mission to lure one of my characters into a trap, raid the assets of the rival, or just plain capture them or one of their companions. This gives you options on who's move it will be. For instance, if the Shadows companion is captured, then it is up to the shadow to go rescue them, or if it is a character of mine that is captured, have the option to either escape with that one or be rescued by another. Maybe a few holo calls between the rivals and allies to give it more meaning (basically i want my rivals to throw insults around). I dont think they should ever directly fight eachother, it would be more of a cat and mouse with maybe a few occasions they look eachother in the eyes here and there.

Also, the level of the characters would affect the complexity of the resulting mission or probability that the companion would even manage to accomplish the initial task. For instance, the level 20 is highly unlikely to capture the level 50. If it does happen though, the level 20 doesnt really have the means to have an amazing fortress on hand. The level 50 though may have his own massive spaceship, or a fleet, or a palace or asteroid facility.

Also, the rewards would be legacy related. And you initiate it, just to have your own little story going.