Played beta way back in 2014. Just recently started playing the 5.2 and 5.3 beta patches after 1 year. List of suggestions.
1. Enemy ships in my Zone of Control- This is annoying for me. Factions should be able to shoot down all ships in their ZOC with no diplomatic penalties and without declaration of war. A kind of cold war. Freighter with trade/cargo modules need to be change so they don't get shot down in enemy ZOC. Give players a pop up warning to confirm if they want to enter enemy ZOC without an "Open Borders" treaty.
2. Civilization/Colony capitals- I think I heard this 9 months ago in a dev steam, they were going to do something about this. Starting a new game or sending my colony ship to colonize a planet the capital gets randomly place on a planet tile, usually in a corner with no other adjacent tiles or capital is stuck right in the middle of 6 tiles. If you go into your home planet after a new game, pop up will ask where you want to place the civilization capital. Pop up after player newly colonized a planet to select colony capital placement. Maybe an ability to move capital or rebuild capital to another tile. Shipyards is another one of those things that need manual placement after completion.
Colony capitals should also be upgraded through techs to give +2 adjacency bonus to all. Colony Capitals should do more instead of just sitting there.
3. Star base Hit Points- each module added should add more 5 HP, more infrastructure means more HP for star bases. A star base with 20 modules added to it has 100 more HP added.
4. Armor/shields/point defense - I think shields/armor should add more defense. Maybe increase all HP by 5X, weapon damage and defense by 5X.
Here's how it works. Shields will add a little bit of missile and kinetic weapon defense, 10-20%. Tier 1 shields (deflectors 2 def) value will get increase to 10 defense, Tier 2 shields (shield systems 4 def) will get increase to 20, etc. Tier 1 deflectors shields will get 10 defense vs beam, 2 defense vs kinetic, and 1 defense vs beam, values of 100%, 20%, 10%.
Tier 1 Armor has 10 defense vs kinetic, 2 def vs missiles and 1 def vs beam. If HP and defense values don't get inflated I wonder how does a 0.1/0.2 armor/shield rating work?
Point defense will not only shoot down missiles now, they will also shoot down fighters from carriers.
5. Super abilities from Gal Civ 2- I already missed some of them already. Maybe Super Abilities from GC2 can make it in GC3 as race traits without changing them to much.
6. Tech trees- I think the tech trees will get another look. I used the Thalan tech tree on a custom race and it seems like a generic one. I really missed some of the techs from gal civ 2 such as the powerful Thalan improvements but expensive and the Iconians planet uniques.
7A. Yor "Assembly" population - I think the default + 2 population for the Yor "Assembly" is a bit expensive at the start of the game. Sometimes I think AI has such a low population, the Yor AI starts to build "Assembly" too late, it slows down their expansion. In all my games the Yor is usually near the bottom in rankings due to this. Maybe add another cheaper/lower tier for the + population, + 1 population for 50% of the cost. Better yet, a slider bar on how much population you want to produce, the more population selected the more manufacturing needed. As you select more production/manufacturing into producing population the ratio becomes better.
7B. Another option would be to make population growth require a planet's production/manufacturing percentage wise. The useless "Population" or "Food" icon on the planet screen is remove for races with the "Synthetic" ability, that way the Synthetic ability doesn't always tie to the Yor tech tree anymore. When you mouse over the Synthetic ability it saids "Disables Food and natural Growth. Instead an Assembly project is use to produce Citizens" This is only true for the Yor. If you're playing a custom race with the Synthetic ability, you are force into selecting the Yor tech tree or you do not get any population growth. The "Assembly" project needs to be added to your list of buildings if you pick the Synthetic ability with other races' tech trees.
7C. Changes: Ability to select other tech trees besides the Yor tech tree playing as a custom race. If other tech trees are selected, farms and population increasing techs are disable.
In place of the "Population/Food" icon is a new slider bar on how much % of the planet's production/manufacturing do players want to spend on population growth for the Synthetic races. Say a Synthetic planet has 40 production, player uses 25% of the production towards population growth, planet only has 30 production left. Maybe new techs for Synthetic races to improve the ratio of production/manufacturing needed to increase population. Or another option in the "Govern" "Economy" screen to drag how much % is spend on population production.
8. Ascension victory - I need 4000 ascension points on a medium map to win. There are only several ascension crystals. I only control one of them now. The points needed for an ascension victory needs to go down, maybe 2-3x, most of them gets taken around the colony rush phase. In GC2 you can win an ascension victory in 100-200 turns, in GC3 it can take 500-1000 turns.
9. A better tech tree interface/UI - Similar to Endless Space or Civilization: Beyond Earth (I have not played but saw videos of Beyond Earth). Their tech tree is a web going in four directions, left, right, up and down, that means you get to see all techs on the same screen at once, no more clicking/scrolling back and forth between screens in each tech category. Players can zoom out and zoom in, filter by tech, name, search, queue research, etc. The tech interface in GC3 might be good 10 years ago for GC2.
9A. For some reason in the tech trees, race specific techs/buildings are not marked, GC2 had icons belonging to the race marking them.
10. There is no stat page. All of your race's stats, current bonuses from techs to stats, etc, There is also no page where you can see what galactic events are active, their effects and how long till event ends.
Changes to abilities:
I think most of the races don't play differently enough in GC3. All of them have an economy, manufacturing, research done the same way, morale the same.
11. Drengin Zealots and Unrelenting abilities: Zealots "Get an Ideology point each time you invade a planet" and Unrelenting "Invasion never cost credits"
Purpose changes - Combine both Zealots and Unrelenting abilities traits into one, Unrelenting or Zealots. This change will make the Unrelenting or Zealots ability and the Drengin race better.
New ability to replace one of the above abilities - "Warmongers" What it does "Gets increase approval for more military power"
11A. Warmongers also gives + 1 content for each race faction is at war with? This might be overpowered on really big maps with 100 races, so forget it if there's nothing preventing it from being overpowered, maybe a cap. Immune to the - content/unrest Ideology that players get if they're at war with that faction. Also if players A and B are in game with "Warmongers", both player A and B get + 1 diplomatic bonus with player C (warmonger ability also), player C with war with player D (no warmonger ability). Diplomatic penalty with other "Warmonger" races if you're not at war with anyone.
12. Krynn Prolific ability - I think this ability is too powerful, especially combine with the + 25% growth race trait the Krynn already gets. In most of my games on large maps, on turn 50 colony phase just ended. The Krynn have about 110 population, everyone else has about 25, second place in population is the Yor who have about 35. This ability reminds me of the "Super Breeder" super ability the Torians had in GC2.
Purpose changes to Prolific ability - "Planets start with 50% more population than is brought on the Colony ship"
13. Thalan - Intuitive and Knowledgeable - Combine the two abilities into Knowledgeable. Replace the Intuitive ability with an ability (Hive mind?) that gives higher approval and additional production/research/economic the more population is on the planet.
14. Synthetic ability - Once you pick this ability, all +content/approval techs are disable. Your race is always content, never getting any bonuses to production/etc. Your race does not need to build any + content/approval buildings.
Galaxy Map
15. No more edge of the galaxy! - Example: When your cursor is at the right middle edge of the galaxy, you can scroll across the edge of the map, it will go to the left middle edge of the map. Likewise if my ships are in the top right corner and I moved them pass the top right corner, my ships will starts to appear in the lower left corner of the galaxy! If I move my ships from the bottom of the map further, they will start appearing at the top of the map. Now every race will be surrounded by other races, no more starting off in a corner of the galaxy.