What kind of system are you looking for? Would you want a system where its like a check to do an RP thing? You could do something like:
-Stats-
Attack (D20 + Attack vs. 10 + Enemy Defense)
Defense
Technology (Ability to use certain devices profeciently)
Support (Healing and Repairing Skill Check)
Synergy (Factor to which you can buff others, and the amount you can be buffed by)
Then, 20pt builds would look like:
-Physical Attacker Stats-
Attack 8
Defense 5
Technology 1
Support 1
Synergy 5
-Sniper Stats-
Attack 10
Defense 3
Technology 4
Support 1
Synergy 2
-Mechanic Stats-
Attack 1
Defense 1
Technology 10
Support 6
Synergy 2
-Communication Stats-
Attack 1
Defense 1
Technology 4
Support 7
Synergy 7
You'd have to make a system behind it or whatever....