GoG Version with integrated community patch very much uninhabitable planets

Only in Dark Avatar or the base game. The max amount of habitable planets has been drastically reduced in Twilight of the Arnor. From what I recall, this was done to reduce the memory usage and allow a bigger map size (Immense).

Still, you should have at least one habitable planet per star system. So, are you absolutely certain you've set the habitability to abundant, and not just the number of planets in general? It's a common mistake. Happens to all of us.

The data for the map generation (number of stars/planets/habitable planets, etc.) is hardcoded. Without access to the source code, it's not possible to change any of this.

You can use cheats to turn all PQ0 worlds into a random PQ1-20 worlds

https://www.galciv.wikia.com/wiki/Cheat

@Gaunathor:

I`ve set both, planets and habitable planets, to abundant, but as I said, I have many star systems without any havitable planets. Often I discover systems with 4 or 5 planets, and each of them is an empty (on the strategic map) planet, class 0.

This is working as intended, it was so in TotA 1.97 or 2.042 and, like Gaunathor already said, there is nothing in the CU that could change that.

However, this

is simply wrong.

In TotA an all-abundant galaxy of whatever size (abundant planets, abundant habitable, even frequent extreme planets) can still have completely empty systems - systems that have 4 or 5 PQ0 planets. It's nothing exceptional, I just generated a few maps using the vanilla game and I have several of these systems on any map.

Interesting thing is, before the Community Patch I had many, many habitable planets with these settings, and nearly no star systems without any habitable planets, even if they were only low class. But now I have an abundance of worthless crappy planets. Another interesting thing is, that I don`t seem to have planets with a quality below 9 or 8. In the version without CP I had often planets with quality 6,5 or 4.

Weird thing that is!

Yes, it's weird in regard as I can't replicate your findings. Generating maps with both 2.20 or 2.042, unveiling them via cheats, and using the PlanetList to count the number of habitable worlds, I see 15-20 for each PQ4, PQ5 & PQ6 in an all-abundant immense sized galaxy. PQ7 alot more, but what's mostly interesting is that 60%-70% of all worlds are uncolonizably PQ0 worlds.

I don't recall what I was playing - probably DA with the AT mod - but I was surprised to find a number of PQ1 worlds, with several PQ2 and PQ3.   Previously observed low was PQ4. 

Max, I just finished an all-Abundant game of TotA 2.20.  By eyeball estimate, 20% of the star systems have no habitable world.

Man it gets even weirder! I just installed the GoG version of GalCiv II (CP) again, started a game, and ALL planets with planet quality of 12 and above are with red dots, I mean, that they are exotic worlds (barren, toxic a.s.o.). All of them!!!! Something with the formula for creating planets is definitely not right!

How is your 'Extreme Planets'-setting in the galaxy-creation setup?

Extreme planets generally tend to have a higher PQ than normal habitable worlds.