I reckon it's a bit early but heck: the earlier the better. Get the developers to think about these issues BEFORE they develop it.
Was playing a bit of Gal Civ II again. Drath Tech is HORRIBLY overpowered on larger maps. War Profiteering. (Shudder). Once you bribe the AI to war, the tech generates at minimum 20,000 credits per turn.
Gal Civ has several issues in all three iterations:
1. AI doesn't put enough engines on its ships.
2. OP combinations. For example, in Gal Civ II War Profiteering + ability to insta-buy starports, colony ships, and factories on your planets = Insta Win.
3. The percentage system doesn't scale well. Universal +% modifiers are too powerful.
4. AI doesn't know how to do the early game colony spam thing.
In other words, balance is a major issue in all three iterations. Game doesn't scale well to larger maps.
So here are my ideas for future iterations of the game:
1. No universal % modifiers. None. Building synergy leads to FIXED production, research or money bonuses. This gets around the problem of exponential growth.
2. The number and type of buildings you can build on a planet is limited by its population. Not enough people? Then there's not enough population to work the buildings.
3. Each star system can only have 1 economic starbase. Every time you build an economic starbase you have to assign it to a specific system. Military starbases, however, can be built anywhere.
4. Economic starbases provide large FIXED boosts to all planets in the system. None of that percentage silliness.
5. Combine shipyards with economic starbases. In other words, starbases are shipyards and vice versa. Makes sense if you think about it.
6. Starbases are the bottleneck for space production. More population = more planetside production. BUT: without an economic star-base, the production can only be used for building stuff on the planet.
7. Make everything that travels in space super expensive relative to buildings on the ground. Make constructor and colony modules ESPECIALLY expensive.
8. Space is dangerous. Traveling into dark, unexplored areas far from your cultural boundaries can cause your ships to die for no reason.
9. Forget about pirates. Instead, there are space monsters that roam the areas outside civilized boundaries. The further from the boundaries, the tougher and the more numerous they become. Use the same template for every monster, but adjust its hit points and damage based on min distance from nearest cultural boundary.
10. Consequently, colony ships are going to need to carry weapons if they intend to travel far from your cultural boundaries.
In other words, turn space travel in Gal Civ into a Dark Souls-like experience. Make space travel more expensive and nerve wracking. The more nerve wracking it becomes, the more rewarding it is if you do it well. It also punishes aggressive early expansion.
Cut corners with your colony ships so you could expand faster? Fine. There be monsters out there that might eat your colony ship.
Also, new colonies don't automatically listen to you. Every time you expand to a new planet, you have to upgrade a "bureaucracy" building in your capital. Otherwise you have no control over what the new colony does. The upgrade and upkeep costs of your "bureaucracy building" scales exponentially so if you want to micromanage you're going to have to pay with in-game currency.
Colonies with large population can become capitals, too, meaning that the player is encouraged to build up the population of new colonies so they can avoid the problem of exponentially more expensive bureaucracy upgrades.