So I've been playing two concurrent Galaxies test games in my spare time, and have this revised version of the ships costs, costs to research each class, and upkeep:
CP is the number of Construction Points the unit has, while RC is the number of EP that needs to be spent by the player to unlock a unit of that class at each tech level. For example, a Tech Level 1 Battleship has 35 Construction Points and costs the player 39 EP to unlock - a number based on the ship's CP plus its Tech Era and command cost.
Under this system, players also have a set number of "total" Research Costs worth of units in each Tech Level. In Tech Level 1, the players can have 132 EP worth of Research Cost in Units. In Tech Level 2, 144. In 3, 156, in 4, 168, and in 5, 180.
As before, you need to research all the units in a Tech Level before you can research any from the next, but you can research the units in a given Tech Level in any order you see fit, at any rate you see fit by spending EP.
So here's an example of what the United Federation of Planet's TL1 Roster could look like:
for 132 total research cost of unit types, notably no new ground units - the Federation player will just have to use universal ground units until they research a new one at TL2, assuming their roster includes a ground unit in the TL2 set of units.
In order to generate faction diversity and meaningful difference, I've also experimented with the idea that each Tech Level gives the faction access to a set number (4 seems good) of new special ship, base, or flight abilities. This means that each faction has access to slightly different sets of abilities, though there are five initial abilities every faction would start with.
Thus, when building a faction's roster of units, you would be selecting units to make up the 'right' number of available Research Cost points with the special abilities you have access to, making faction building an interesting and strategic part of the game.
Blue? Green? Red? Refuse? It's time to talk about rules for a new community edition of the VBAM rules!