Hey I was thinking about a cool feature that could be added to the game using legacy system. Legacy missions! Now this has probably been suggested before, but my idea is that if you get a character to max level and complete chapter 3 of their story, you can purchase a legacy perk that marks that character as the target for the Legacy mission. Only one character of each class in the legacy can unlock this perk, so choose wisely.
Anyways what purchasing this perk does is unlocks two Legacy missions, one for Imperial, and one for Republic, and in these missions you get to play alongside your own character and their companions (excluding HK and Treek), or against them.
For example, let's do the Jedi Knight and an example of their Legacy missions
Republic side: Light in the dark
Description: Your victories for the Republic are many and well known, but now another Republic hero calls for your aid. Jedi Master <Legacy Character Name> has been tasked by Grandmaster Satele Shan with raiding the Sith Acadamy on Korriban in order to save a Jedi bearing vital information, this mission is extremely dangerous, but with two of the Republic's greatest heroes on the task, victory should be possible, and this war will take a major swing in the Republic's favor.
Imperial side: Extinguish them
Description: This is a dark day for the Empire, whispers and rumors say that a Jedi snuck into Dromund Kaas and attacked the emperor himself during meditation, then escaped afterwords after proving unable to strike him down. to raise a hand against the emperor is the highest of crimes, and we have traced him/her to a Republic Warship in the outer rim, board the ship, find him/her, then cut them down and anyone who dares protect him/her. For the glory of the Empire!
Anyways that's just an example of the mission in question, in the allies mission they would play as an NPC where they would aid you in completing the objective, while the enemies would be forced to fight their way though an area to get to their target and defeat them, and kill/spare/capture them however your Light Side/Dark Side fancies. The missions are non-cannon of course, but it would be fun to see just doing a mission alongside a character you created yourself.