Regarding research, I did some research (no pun intended), and I did some test's, I think that an exact uniform build/research system is needed for all races, (maybe even replacing the vaygar and higaran ones in time) while the novelty of having the exact same tech trees as the original games (cataclysm, homeworld), sounds cool, in-fact it requires a lot of work and the results won’t play any different to what I'm going to propose.
My suggestion is to mimic the current tech tree and build system used by the taiidan/kushan (IE. all utility ships unlocked from the start, once a facility is built, all ships in that facility can be built ect.) with some minor changes, and to clarify, when I'm talking about keeping building and research the same, I mean structure, not build time/cost, research time/cost.
To start with remove the research for:
- SCOUT ENHACED SENSORS
- REPAIR ABILITY
- IMPROVED TORPEDOES
- IMPROVED BOMBERS
- SCOUT EMP
And any other research related to unlocking specific ships or giving specific ships, weapon boosts or ship ability's other then cloak and hyperspace, instead make them innate and possibly increase cost and build time of the ship to compensate, the reason for this is not just to reduce work overhead which will have to be done, but once you start making race unique complex tech trees with individual ship ability and weapon research, it starts creating lots and lots of balance and AI problems unless you kept the exact same ability research the same for each race (which would seem pointless as I would not expect all races scouts to use senor ping and emp for example).
By making all the tech trees/build trees the same balance becomes easier to manage, as ship production and research become available to each race at more or less the same time, (instead of trying to balance ships through completely different research trees) and of course ships within races become more manageable for example:
Say you have one fighter that is really good, and one that is basic, they have the same role, just one is faster and does more damage than the other, you would assume you would pick and build the best one right?, well not really, you see even though they become unlocked at the same time (I.E you don't spend money and time researching “lazorz guns” to build a “lazorz gun fighter”-_-), they would have different cost and build times to reflect that, which you would have to consider, the same if they where cheaper, built faster, but required research.
By using a uniform build/research system for each race (where possible), even though your making research and building the same, the races will not play the same as each other due to multiple variations in ships, research times/costs, build times/costs.
Of course what I say is heresy, as it doesn't reflect exactly any tech tree in any homeworld game, but the end result will be exactly the same as you had a different build and research trees for each race, however this is just an idea and its your choice, but personally I would prefer balancing ships to trying to balance different tech trees.
Also possibly rename the races shipyard “capital class facility” to “super capital class facility” just to show that it can produce larger ships, (if the name will fit).