- Universal Soil Adapter is mispelt as Universal Soil Adapter_Name. Furthermore it allows to terraform EVERY hex on the entire planet, not just once, but until the whole planet is terraformed, resulting in ridiculous planets. Was this intentional?
It's intentional, yes. It's an end-game tech. They are powerful by definition. There are other end-game techs which hand out +100% research to all planets.
EDIT: Holy crap, it's THERE in the tree? OK, that's getting changed, thanks for reporting 
- Having exact amount of ideology points for an upgrade does not allow it until you have 1 point more. So if you have 40 points and next upgrade is 40 points you cant spend them till you have 41
That would probably be something that's present in vanilla too. It's certainly not something we can affect with modding.
- Colony cost drain initially is still much too severe. Even with dedicated money worlds the player has to essentially rush money production and research early on just to be able to expand. This result in a very linear and inflexible strategy compared to vanilla
It's really not. There's an exponential increase in cost per world, but your ability to bear it increases even more. All it really does is limit your ability to spam colonies early on; by mid-game, a single cash planet can still comfortably support an empire of 25 planets. It just needs to have enough population to do so. You even have access to cash buildings from the start of the game to make it easier (aside from the Yor, who work very differently from everyone else). If you're finding cash drain too high, it means you're colonizing too quickly for your economy to support it. Slow down.
It's not like vanilla. In vanilla, you can largely just spam colony ships until the planets run out, with 0.1 population on each, and surf on a wave of free production from colony capitals. Adding a colony requires no thought, because no matter how bad it is, it is always better to have a colony than not. This is an old problem in 4X games; it's referred to as 'Infinite City Sprawl' in reference to the optimal strategy in Civ 1 being to have as many cities as tightly packed as possible. This led to multiplayer games that were largely just a race to settle as many cities as possible in the shortest space of time, with no real effort to build them up - which is also what we can see in GC3 MP presently. Mad colony rushing can basically defeat any other strategy.
Civ4 (and this mod) combated ICS by using a maintenance system. While maintenance doesn't actually stop more cities being better than few in the late-game, it makes every new city a net loss to the empire until it's built up a bit. I changes a new addition to the empire from an immediate pay-out to an investment, which will be useful later but is initially a cost.
You have 5000 credits to start; don't spend all of it on rush-buying. You can spend some, but the more of it you spend now, the less time you have to get some real cash generation online. Rush buying is much, much cheaper than vanilla, so you can get away with doing more... but just remember, you're eating into your runway. Expect to lose money for the first 50 turns or so; you can afford to, and it's not something to panic about. The question is more about how much you can afford to lose per turn. You must actually take some time to think about how you are running your empire's economy, rather than leaving it to run itself.
The number of cash generating planets you decide to use is debatable. The more you have, the faster you can expand, but the slower your research and production will be. Later on, they'll all produce absolute buckets of cash (one late-game cash world can probably support an empire of 50 planets on it's own, though fleets are by far the biggest expense by that point). If you find yourself needing more cash, it means you're expanding faster than your population can really support.
Population is vitally important. Like, really. Waaaaaaaay more so than vanilla. You don't want to be sending out colony ships which are less than half full early on; you REALLY don't want to be sending them out with 0.1 population. The colonies they produce will take anything upto 100 turns before they can even pay for themselves, let alone offer a surplus. Do not be afraid to stop colonizing, or just park colony ships in orbit, until there is sufficient population to fill them up. Oh, and seriously, specialize them per planet. Colony capitals can build most improvements by themselves in about 6 turns, so feel free to put everyone into whatever they're going to be eventually doing immediately.
Oh, and finally - fewer high-pop, highly developed planets are often much more powerful than more low-pop undeveloped planets. Population can grow to be enormous, and as you noted it's possible to unlock every hex on the planet eventually, so the difference between a mature world and an immature one is colossal. The largest empire is not automatically the most powerful now - it has the most potential, but is unlikely to be as strong in the short term as a smaller empire.
It really boils down to this: In this mod, there are times when it is better not to take a planet. It is up to the player to judge when those times are. Early settling pays off later, but hurts in the short-term; late colonizing makes life a lot easier early on, but means you may miss the best planets and the empires which DID expand early might be stronger than you in the mid-game.
