We don't know much about these new upgrades, just this: "With its forward battery armament of four dice, the Phoenix Home might appear a natural fit for the sort of direct Rebel strategy enabled by the Liberty Expansion Pack from Wave IV. However, the real strength of this vessel lies not in its forward attack dice but in its new Fleet Command upgrade icon. You can only equip one of these upgrades to your Phoenix Home, and all three of the Fleet Command upgrades that come in this pack are unique. Nonetheless, for a handful of fleet points, each of them allows you to spend command tokens to power advantages across every ship or squadron in your fleet!"
Phoenix Home is a natural fit for Fleet Commands, being the heart of the early Rebel fleet. However, I think we can all agree that it doesn't make sense to stop there. Home One commanded even more ships than that. The Devastator commanded ships (and the Executor commanded even more). Think we will see an upgrade to add a Fleet Command upgrade slot to a ship that doesn't already have one?
This is just spitballing, except that I'd like to ask people who have been around for several waves of the X-Wing game. When something new like this comes around, does FFG retcon it onto older pieces?