Even if low-tech/midline/high-tech seem cheesy, they work. Low-tech has that rugged, simple but effective feel and style. Midline has sleek angular space wedges or blocks with bullets and laser beams. High-tech has fancy and curvy blue saucers or pimples that rely too much on energy and fancy tricks. Phase ships with their dark and purple I, T, and X shapes feel like a completely different faction from conventional high-tech, more like its own style or a mod faction.
It probably would be harder for me to remember which of the Mastery/Core/Expansion from the Starfarer days go to which epoch. Without reading lore, I would probably guess Core is low-tech, Expansion for midline, and Mastery for high-tech. Not Mastery for low, Core for mid, and Expansion for high.