Just as a random note, but you can provide a lot of 'commands' to keep officers in the pool by running carriers + fighters. Set the fighters to your lowest rank (Lieutenant Commander for me), build a bunch, and folks will happily ride those fighters up.
I've managed to get like two Vice Admirals in a Lieutenant Commander -> Commander -> Captain -> Commodore -> Rear Admiral -> Vice Admiral structure in my current game by a combination of spamming fighters for Lieutenant Commanders, cheapie frigates for Commanders, and letting Captains pilot whatever's at the top. Although right now it's kinda... my light cruisers are a Captain slot, the strike cruisers are a commodore slot, Destroyers just got bumped down to a Commander slow, and all the frigates are now Lieutenant Commander slots. Although the downside is I've got 2 VA, like 11 Rear Admirals at the moment (fff), and I'm not willing to keep shoehorning out task forces just to keep some of the crummier admirals, so some of my top-end commands are going to keeping them in the loop.
Still, if you don't mind keeping track of all the task forces, that can be a good way to keep a rank 3 or up happily alive, while potentially making use of the myriads of rank 1s who have absolutely no crew training score.
