Explorable ships would be neat, like getting a quest to find the spy on your own ship would or just walking around.

But please give up on player crews, its a terrible idea and I'm certain the devs came to the same conclusion. For every fun moment of a fully manned vehicle in battlefield, there are 20 where some moron is the driver and keeps getting stuck on things, or worse. What happens if you join a ship who's captain put max points into the 'ramming speed' talent. Or the targeting guy goes afk =/