Have different classes / species of crewmen depending on the system you're in, and/or your affinities with given factions, and each could have pros and cons, like a given race could have +20% movement speed in ships, another could breathe in space and have 100% more speed outside ships, another could carry twice as much energy but have 20% less speed, etc, etc. Kinda like Faster Than Light, ngl, but I really think it is among the many things that could make managing, and thinking your crew layout ahead something more meaningful and interesting, atm it just feels like pressing a button whenever you can. It's a shame really especially when you see that they all have names, different hairstyles etc, but at the end of the day you don't really care for them. Having some sort of XP system as where they'd get better at something the longer they do it, but they could not become like excellent at everything (like if a crewman who's experienced in manning weapons stars supplying engines more often, he'd get better at supplying engines but his weapon proficiency would decay), and crewmen would also go to roles they're better at similar to an extra priority system balanced with the distance to subsystems etc
Another idea would also be having a captain for your ships when they have at least 40 or 50 crewmen, with some sort of skill tree, and he'd look different and sit in the cockpit/bridge ; and after for each say 80 crew members that could make a lieutenant pop in the ship that could boost nearby crew members for instance ; parts related to chain of command could be added, like officers quarters and speakers to relay orders (those are just ideas on the fly though :p)
What do you think about that? Any suggestions, and other ideas about crewmen?