Just a few ideas I have are just rough with no stats but a general premise.
ZEALOT- You stand for a cause with unwavering determination. Doesn't necessarily have to be religious in nature.
GAMBLER- In an era of space exploration you bet your life everyday. Just so happens you're either really lucky or stacking the deck.
One idea about themes I would really like to see is branching options as you progress through each theme to help better build a theme that works for each character. Some are so specific that they seem quite useless unless a specific situation occurs while the ACE PILOT's are much more useful by comparison.