In my case it would be addition of "crazy science" which can be either researched or found. Some examples include:
1. Atmosphere remover, which creates a wormhole to "somewhere" and suck atmosphere out of the body allowing you to easily colonies and terraform Venusian planets (for balance reasons it would be one use item).
2. Gas giant ignitor, which can turn a gas giant or a brown dwarf into a miniature star, allowing you to colonize and terraform their moons that were far too cold previously (always a one use item).
3. Link destroyer/creator that would allow you to destroy an inconvenient jump connection (or to create a convenient one) without resorting to SMing.
4. Superscale habitats like McKendree cylinders, Bank's Orbitals or maybe small (3mln kilometers) ringworlds around those useless white dwarfs.
5. Matter transmuter that would would be deployed close to a star (in the same way fuel harvesters are deployed around gas giants) manufacturing TN elements for free.
You've played Space Empires IV & V before haven't you?
2. More ways to generate revenue, preferably though some kind of ship component (like solar power satellites).
and Alpha Centauri too I see.
Other things I'd also like to see, but are unlikely to be added are:
1. Ability to make a custom star system. Recently I play much less campaigns with all powers starting on Earth and more scenarios with several powers starting in different star systems and getting a reasonable one via random generation is a friggin' nightmare, especially when you want a somewhat specific system for RP purposes.
This would of made my Freelancer based campaign so much easier to make. Even if you could just SM a star's stats and let it generate the system by itself. Or SM planetary bodies' mass, radius and moons.
Some things I would like to see:
1. Have surveys store the data within the computer banks of the ship instead of simply auto-downloading to the capital. Be able to transfer the data to other ships at close range (laser transmission); through the use of long range communication arrays; through messenger ships, drones, fighters or missiles, which are collected by another of your ships or colonies; or by landing inside a hanger of a mothership. The ability to intercept, jam or steal this information would be nice as well.
2. Have intelligence be split into:
SIGINT - Monitors information sent over radio waves and so forth (like geological survey data or position updates)
MASINT - Measurement and signature intelligence, to identify ship classes and abilities from thermal, EM and mass measurements.
HUMINT - Human intelligence using people in the field, whether that is: Covert Ops teams, Interrogations, interviews, espionage agents, etc.
TECHINT - Reverse engineers plans, ships and technology from salvage and acquired equipment.
OSINT - Free, open-sourced information, gathered from the enemies own transmissions (such as the internet).
GEOINT - Visual images of planets are used to determine population sizes, infrastructure, number of buildings, troop movement, etc.
BIOINT - The medical and biological information of a race, to help with interrogation, making bio-weapons or treating prisoners.
FININT - Information on wealth, taxes, expenses, corporation assets and stock dividends, foreign aid and foreign trade routes.
COUNTERINT - Monitors ways into the nation, as well as observes foreign diplomats and any high risk individuals.
When I choose to conduct espionage, I don't want to always send a 5 man team into enemy territory without any sort of objective besides "find stuff". It would be nice to gather information on neutral factions without having to resort to water boarding prisoners, or having special forces teams steal blueprints for (I would assume) publicly known colony ship classes.
