Thanks very much to all of you for your enthusiastic comments and questions and suggestions on the mod! It's very nice, and I do appreciate both cheers and frowns.
It seems to be about time for me to re-state some of the reasons for the values of the large cultural facilities.
In 3.0 there are two kinds of Cultural Center, homeworld and colony. In 2.5 there were as well, but they were identical except in name. In 3.0, the colony Version costs a lot less (2.4 million x 3 types) while the homeworld Version costs 4 million x 3 types, and has even better values.
As in earlier Versions, these costs are so high because you are NOT supposed to consider building them, unless you are trying an extreme stategy or an extremely long-term (and peaceful) game. In fact, the main reason they used to cost so LITTLE, was because when you started with a bunch of them, you might consider SCRAPPING one for the resources (which more than one player has done when they failed to manage their budget properly).
With one available at 2.4 (x3) million, however, it is possible to consider actually building one as a long-term strategy or goal, which is kind of an amusing tease, so I have left that in.
To explain further, Proportions is kind of a counterpoint to the things that don't make sense in the default game mechanics. One main thing that does not make sense is the way that research facilities add directly to one giant empire research pool. That only makes sense for something like a big basic computer problem that is already understood and can be divided amongst computers. Real estate space is not the obstacle to research rate, but the stock game makes it so. So the point of a cultural center is that it should be unique to the homeworld and NOT reproducable... or at least, not without extreme difficulty. Creating a new CC does not represent simply building up a new planetary infrastructure, but also developing new technologies that work well on a completely alien planet (with different gravity, pressure, atmosphere, flora and fauna, weather, temperature, seasons, etc), and perhaps even more importantly, developing a new _civilization_ which is different enough from your original civilization, to see things from a different perspective, so that it can in fact make a huge increase to your empire's abilities, beyond just adding some more factories and labs.
So that's basically why Cultural Centers are nearly unbuildable, on purpose.
Arcologies are massive undertakings themselves, vast pinacles of futuristic community construction, so it makes sense that they take at least 10 years or so to build on a good planet without miraculous technology and/or many millions of people or droids hard at work. On a good planet, they will eventually be worth it, too, especially thanks to the multipliers, but again it is a big investment of time and research. Perhaps unwise to do during war time... unless it will be a 20-year war or a low-intensity one. Rome wasn't built in a day, and neither will an arcology be.
Again, these things are included as the far end of the spectrum of short- to long-term non-military investments. They are not supposed to be done routinely, and they are not supposed to necessarily be a good idea, especially in a crisis. An MP game of Proportions should probably generally represent something of a time of crisis. Starting on a new map without running any turns for history, it represents the initial wave of expansion and colonization by several empires at the same time. The priority is probably to claim as much territory as possible, and perhaps to conquer an alien homeworld or establish an alliance to guarantee that the future will turn out well. Building new civilizations or wonders of architecture may not be the wisest investment during such a time. That's not a reason to not include them as a possible choice, however.
The intermediate cultural facilities offer a spectrum of investment levels to choose between, and I think now with the multipliers, there are now much better (and in fact, good) reasons to consider some which were of more dubious value in 2.5. For particular examples, the Settlements and Communities used to be kind of cheap but not very helpful in 2.5, but in 3.0 their multipliers offer a good reason to use them on production or research colonies that in 2.5 might not have wanted any cultural facility, and they also offer Organic multipliers which the _urban_ cultural facilities do not. The increased scarcity and needs for Organics in 3.0 also make Agrarian facilities much more desirable than in 2.5.
Similarly, some of the higher technology items may also turn out to be very inefficient investments in most cases. Again, this is intentional. Not every new invention makes older designs obsolete, or is the best thing to use. Some inventions may offer unique abilities, but be impractically expensive or large or whatever. But the option remains, and in some cases, items which seem pointless may find situations where they can be put to good use, or provide a solution that would otherwise be impossible. Players should find many more occasions to think about what levels of technology to develop and to deploy, instead of simply in what order to max out which technology, as is often the case in the unmodded game.
I hope that helps explain and makes good clear sense.
(Also, I hope people are planning to continue playing after SEV comes out.)
PvK