Some additional impressions from gameplay.
1) Possible bug: When I switched to Republic Gov't a tip onscreen stated I would have 2 additional policy choice but it appears I got only one.
2) I'm getting an awful lot of statues built in my honor from Governors that like me. Yes I like the 10 control points, but this is going to blow up as I get more governors that like me. Maybe a little less frequency on this. Same with the festival but to a lesser extent.
3) Another bug: On the leader screen, when you drag a leader to a planet card, it sometimes rejects them and you have to leave the screen, go to the galaxy screen to find the planet, and assign the governor there. But worse, on that leader screen it sometimes not only rejects assigning the governor to the planet you pick, but instead assigns them to another planet!
4) Colonies and asteroids by default are assigned to the nearest core world ( or maybe colony). I'd like to be able to change what core world colony or asteroid cluster supports. Similar to GC3.
5) Extreme planets are so small. None of them are Medium, Large or Giant. So you have these small extreme planets that are not of much use but you may need to change them to a Core World to get the resource on it. Giving you a size 5 extreme planet that you 1) had to wait to get technology to colonize it, 2) Turn it into a puny core world to get the resource. Make some of these planets larger, say size 13-16.
6) More variety in the sizes of Giant planets. Other than my Terran Homeworld, which starts as size 24 (large) which I boost ASAP to 26 (Giant) I've only found size 77s. Let's see some in between. Size 28, 33, 40 etc. Better yet, make it size 35 and you need extreme colonization to colonize it. In fact, make some really juicy planets that are hard to get to, but if you do it's a big boost. Size 40, with a couple of much needed resources or artifacts, but Extreme and is surrounded by space monsters. Including one which sits in orbit of the planet and won't let you colonize it. I think Master of Orion pulled that trick. I remember in GC1 where if you found a purple star, it was guarenteed to have large planet. Seems the AI knew it too, and there would be a race to colonize the planet. Bring that back.
7) We need a screen showing all empires discovered and their relative strengths compared to you and to each other, as in previous versions of GC. Including there trade relationships and diplomatic status with each race.
8) Previously, the most common resources (Durantium, Thulium and Eridium and Antimatter) were mined in various places. You could get a lot of them but they were used extensively and you could still have a resource shortage. Easily. Nearly every system in every ship you built had specific needs. This was a good game mechanic, but this no longer seems to be the case. And now you can mine these resources but have no need to. I am so far barely using any of the big 4 resources. And building certain starbase modules is now dependent on Techapod Hive?, a really rare resource. It was better the other way. Specific types of weapons used specific resources. Same with engines, armor etc. GC3 had something else good (mostly I was unimpressed with GC3) in that you could have lesser versions of a weapon which didn't need the resource. So you got to say Lvl 3 Missiles, and you got 2 versions, one needing antimatter and a less powerful one (or it took up more space on your ship) that didn't use the resource. Maybe this could be implemented here.
9) I've only gotten to Small Hulls so far. But are there techs that allow miniaturization so that I can get more equipment into the same size hull? I really hope so.
Well, that's all for now,. I've cut off Prestige Victory on this game, so I'm getting farther and can make more suggestions.