[PvK]

Uuf... I catch the flu and fall way behind on this discussion. Actually, it's probably good to not to be always chiming in immediately, but it will be a while before I can cover everything. I will just throw in some ideas.

* Upgrades and return-on-investment times are generally things I have studied and done deliberately. That is, I expect people to consider upgrading from a city to a metropolis, instead of building a metropolis from scratch. It also makes more sense - metropoli are generally cities for a long time before they become metropoli.

* There is a major effect of lag and return-on-investment to be considered. The question of "which construction path is best?" can only be answered if you first answer the question "how soon do you need a return on your investment?" Often the best thing is to build as many small-scale facilities as possible first, and then build larger facilities one at a time. The dilemma becomes, that this makes the upgrade technique start to become impractical, because SE4 only lets you upgrade ALL facilities of a type at once. So, you end up with a huge spectrum of possible ways to develop, and many of them are "the best" for different times by which you want the return.

* Having said that, I wouldn't consider it "wrong" to increase the facility upgrade cost. I think anything in the 50-100% range will work well. Below 50% will start to cause unintended effects.

* The "upgrade a house to a castle" argument doesn't really apply, I think, because facility "slots" should not be taken to literally represent real estate limits. Planets are enormous, and upgrading from say, a city to a metropolis, does not necessarily require doing anything problematic to the city.

PvK