Definitely need the ability to promote one of our bridge officers to First Officer. Benefits anyone?
Frees up whatever slot that officer occupied
Adds a bonus to ship movement, weapons, and repair(First Officer can go "encourage" crews to work harder while the Captain commands the ship
Unique powers and missions
I like this idea. My current ship is a Nova-class, and my tactical officer is sitting in the "First Officer" chair (its the "Voyager" looking bridge). Having the choice to make him first officer would definately be a good feature! Would bring that extra tad of Star Trek to the bridge that we all know and love. Oh and a bonus depending on your XO's class would be nice!
A First Officer, or Executive Officer, is the guy that runs the ship so the Captain doesn't have to. In essence, what he does is manage the crew and the ship in such a way as to keep them at optimum levels of proficiency so that when the Captain gives an order everything works well enough without too many problems that can't be handled the lower echelons of the chain of command on the ship.
How could this be best translated as an BO?
Well, I had this idea that the First Officer might be the guy that goes on an away mission instead of the Captain, although in my opinion sending either officer on an away mission is about as dumb as blowing your genitals off with a shotgun filled with deer slugs, and then doing it again. Both officers are essential, and to send them on an away mission takes them away from the bridge where they need to be the most. I'm not saying there is absolutely no reason that either officer should go on an away mission, but at the very least there ought to be an option for who gets to lead the away team.
The best thing for an XO to be is as an extra bridge slot that gives you one extra ability to use. Maybe with him on board you get an extra Attack Maneuver, or maybe you get a bonus to Crew Recovery, or maybe you shoot faster.