The tl;dr version: Create a way to assign specific roles to crew members so that they will take over from lesser experienced crew when entering a room.
The longer version: I like the way that crew members gain experience in the game when they man certain consoles (weapons, shields, engines, piloting). But when I wind up with a lot of crew members, I'll sometimes stack them in the rooms so that the extras can either fight off intruders, put out fires, or repair damage quicker. The problem comes in when I send the more experienced crew member to sickbay to heal. The lesser experienced one takes over (not a problem) but doesn't give up the post when the more experienced crew member comes back (small annoyance). I have to shuffle them around to get them back the way I want them to be.
My proposed fix is a minor one: have four slots on the crew list on the left side of the screen, one for each mannable station. A player can then drag a crew's profile to each slot, assigning them to that station. If they are in the room with that station, they will automatically take over. If they're not, anyone can take over.
It's a minor tweak but I don't think it'd upset the balance of the game at all.