Sorry if I am a little late to the discussion, but here are some ideas for the game. Please bear in mind that I am saying this in reference to GC2 and changes may already have been made in GC3.

Diplomacy options

1) Right of passage for "X" turns- Somehow if I am invading someone on the other side of the map and my transports pass through a third one's area of influence he declares war.

2) Loan of Armies/Planets for "X" turns- Loaning the planet to ally. Potential benefits include range benefit, repair benefit, manufacture from the world your own design using the planet's manufacturing points.

3) Coalition- 2 people (including myself) going to war with a third person simultaneously.

Battle Mechanics

--> In GC2 the full battle completes in the same turn. What I am suggesting is that per parsec ships do only 1 attack. It means if a ship has 20 hp and 2 laser , another 40 hp and 5 laser , then next move hp becomes 15 and 38 respectively and not 0. So it will mean long drawn wars and repair , ship speed to outrun (or kite) will also be a significant factor in battles.

Trade Mechanics

--> Trade route limit should be based on distance and not a number say 8. It means longer routes yield more money but you can have less of them. Shorter routes yield less , cost more frieghters to completely saturate but you can have more of them. It means you still retain your fundamental idea of longer trade routes but equal income with short ones.

Ideology Suggestion

--> After watching few dev. streams on youtube I feel Ideology is not flexible. Eliminate escalating costs on Ideology but add escalating ideology points as turns progress. This means a decision now is less important than in the future (in terms of unlocking bonuses). So in theory in the end game I can unlock an ultra powerful good ideology bonus or 2-3 small evil bonuses. Also change diplomacy so that the opponent views you more on your recent ideology choice than cumulative choices.

Thanks for reading and constructive criticism is appreciated. And thanks for making a truly awesome game in GC2 and looking forward to playing GC3 when it is ready!