i'd like to see each faction get their own special variants at least, if not their own ships. i think the factions should be expanded in a few ways.
1. favored strategy, favored ships. this is already sort of in place with the lion's guard sindrian detachments; they have a very specialized sort of ethos, but can be expanded for every faction. each faction should have a particular strategy they like. the hegemony's is basically already in place, huge, heavily plated ships of the line in large formations. likewise, their nemesis tri-tachyon favors smaller formations of stealthy raiding ships, or line ships of enormous high-powered shields.
i'd like to see sindrians go carrier/fighter heavy, and ludd, sticking to their religious theme can be fanaticism, perhaps with variants designed with safety overrides, heavier fixed torpedo mounts and other dangerous modifications (both to the user and the enemy)
anyway, that can go in many directions, but each faction's fleets should be relatively uniquely composed, and each elite formation (lion's guards, hegemony has one AFAIK) should be doubly unique.
2. the way they behave should differ, whether they tend towards war or peace, diplomacy or violence, et cetera. what goods do they sell? what do they manufacture? how tolerant are they of independents? etc. should all vary.
anyway, yes i'd really like to see a heron painted up in lion's guard colors, and carriers need the help anyway.