Hey, I was looking over the civilizations while thinking of UUs and had some suggestions for the leaders.
Galactic Senate, perhaps add someone like Padme' into this civ;
Mandalorians, Mandalore the First and perhaps Boba Fett;
Quarrens, Tikkes or some other leader as a second;
Sith Empire, I would probobly replace Malak and Nihilous with Naga Sadow or Ludo Kressh and either Darth Revan or Exar Kun;
Rebel Alliance, Replace Mon Mothma with Admiral Ackbar;
Chiss Empire, Chaf'orm'bintrano and and Shawnkyr Nuruodo. If I remember correctly, Thrawn was an outcast before rising to the position of Grand Admiral in the Imperial Navy;
Hutt Empire, Borga Besadii Diori and extend Jabba's name to his full Jabba Desilijic Tiure;
Black Sun, add Alexi Garyn;
New Republic, Borsk Fey'lya (use full name) and Mon Mothma;
Yuuzhan Vong, Warmaster Tsavong Lah and Shimrra Jamaane
or Nom Anor
Rakatan Infinite Empire, Leave The One and add in Orsaa or Ll'awa
Ok, that's my two cents
NEW_Rome