An idea that came up in a discord discussion; having the ability to move crew members around as pilots of other ships while taking their specific abilities with them to the new ship. Whoever they replace would take their old spot. It seems like it'd be a nice way to switch up the fleet mode and possibly replicate the effect of mods for characters.
You'd only be able to use pilots of ships that you have unlocked, and you'd still need to activate the pilot to be able to activate their unique ship and upgrade their ability.
Edit: For obvious reasons, this wouldn't be available to the Fleet Commanders unless every capital ship's ultimate was either moved to the ship or moved to the fleet commander themselves. And it would only be between the capital ships if it were available.