Hi Shadowclaw.
1) Who is my worst enemy in late eras? Inflation. Major economy disaster is worst problem. I am now in late Transhuman era (Gigantic map, 48 well-developed Earth cities, 8 Lunar cities, 10 Cislunar cities, 4 Venus cities, 7 Martian Cities, 5 Solar system (Jupiter, Neptune etc.) cities). I have huge economic difficulties, because of inflation 1000+ %. Maybe you can add some anti-inflation buildings?
I agree. I'm not sure how to do anti-inflation buildings; does anyone know? E.g. is there a building in the main mod that I can use as a template? However, I can do more maintenance reduction in space buildings.
Part of the problem may be that space buildings and cities are still weaker than I think they ought to be, and those buildings ought to be boosted some more. It may be that all the non-Earth buildings are adding too much to maintenance without providing enough benefits to justify their cost. Another issue is building consolidation, and maybe there isn't enough new good to make up for the gold lost from old buildings going obsolete.
I've found also that if you take over the world and get to the Galactic Era, then funny things start happening with gold and research, as though some kind of overflow bug is being triggered. I don't think it's my fault, except insofar as I added more content to get into overflow territory, and I don't know what to do about it or if some kind of computational bug is causing you problems.
2) Is V7 savebreaking? Is it better finish my current game on V6?
It shouldn't be. I can't think of anything that would break a saved game. At any rate, V7 is still a ways off because I just started a new job and have to give that full attention now. Just in case, back up the V6 modmod before upgrading.
3) Utility fog building is unusable currently, because of "small chance of nuclear meltdown". Is it possible make this "chance" obsolete after some tech? Other buildings with "nuclear meltdown chances" are unusable too.
I don't know if there is any way to make the meltdown chance go away. I always edit it out of XML files for my own play, because meltdowns are a big pain in the butt. One solution is to have the Utility Fog be replaced a bit later in the tech tree by a safe version, just as we know have safe Generation IV nuclear reactors replacing the older nukes.
4) We have amazing Atompunk tech, but it is disabled. Why?
Very good question. Does anyone know? I think it ought to be enabled by default. While we're at it, what about Nanopunk?
I'm glad you are enjoying the game and I hope you will be able to make it through the interstellar material too. There's a lot more of that coming in V7.