So, I suspect I am opening a can of worms here, but there are a few well known issues that create a lot of havoc on gigantic galaxies over all older revisions of GC II. Most of us gig abundant players have found ways of living with them, but I suspect immense galaxies will just make them worse. I am reluctant to try an immense game until I know whether these things will still be a problem.
I should say I have NOT yet tried a TA immense map and, unfortunately, there is no way to see if these have been resolved until you are very deep into a game.
In order of importance and frequency:
1) Ships randomly ships loose their autopilot directions every turn. This is a really big problem when the map is huge and I've seen it on maps as small as large and I've seen it with less than 100 ships under my control. The only solution is to cycle through every ship on the map with movement points and give it new directions over again, every single turn.
BTW subset problem, sending all ships without a destination to a destination used to include the starbases and would lock the game if you hit the turn button without deselecting the starbases, so this was out. Haven't tried that path recently to see if it was resolved.
2) Newly built ship notification pop up on right hand side of screen stops popping up...Eventually planetary build queue notifications will also start disappearing. I've seen two solutions. Set all planets with autopilot destinations. Or (the one I use) have no ships in orbit around any planets and periodically visually scan the entire map for shield icons. In addition, never use the last planet on a tile until you have scheduled the final building type for all squares. This way you can sort for planets that are doing nothing and look for ones that have a (x) next to them, indicating an unbuilt square.
3) Planetary pop up list can't list all the planets (DA forward). You may have fixed this one, not sure.
4) On game load, some ships will pick a new destination and head there. It's usually a far border of the map.
I believe that I have already submitted bug reports on the first two with maps that were extremely overbuilt (and consequently sure to demonstrate this problem every turn). While the submitted games were not typical, they were excellent examples of repeatability. These problems do occur on games that are very much unfinished.
Let me be clear. I'm NOT trying to bash the game or SD. I like the game and SD. I'm just not wanting to deal with these issues on an immense scale.
Any light you can shed on this would be much appreciated.