This might not work for vanilla but it could be neat for mods. Six new crew:
Starfarers: Crew that raise a ships CR to 90%. (I think that's correct, it goes 50-60-70-80 based on rank, correct?)
Special Forces: Marines with 150% chance for boarding action successes
Fighter Aces: Crew that raise fighter's CR's to 90%, but can only be used in fighters
I think to balance them, you couldn't buy them. They can only be trained in combat, or awarded for particularly hard missions or boarding actions. And they grow slow, only one or two for a mission of 50,000 XP. Aces could only be trained in battles with fighters of course.
Also, on the lower end:
Drone Crew: Do not cost logistics, and use half the supply. Count towards both crew and cargo space. Can be manufactured. Crew bonus capped at 60%. 50% Higher survival rate
Android Crew: Do not cost logistics, and use double the supply. Count towards both crew and cargo space. Can be manufactured. Crew bonus capped at 70%. 75% Higher survival rate.
Cyborg Crew: Cost half the logistics, but double the supply. Crew bonus capped at 80%. Can be manufactured. 100% higher survival rate.
