I spent a lot of time this weekend playing around with this issue, and have a few game-balance and game-play issues and suggestions to make.
First, the econ improvement chain is totally broken. As near as I can tell, "Market Center" -> "Adv. Market Canter" is the only upgrade that works. Adv. Market Centers do not upgrade to anything later in the chain, nor do Trade Centers or Banks. These latter two aren't much of an issue because of item two. Are these breaks intentional, or just messed up data?
Second, the econ bonuses for the econ improvements are totally out of whack. The bonuses peak at 15% with a Trade Center, go down to 12% for a bank, and then down to 10% for a stock exchange.
Third, it's faster to build an extreme sports arena than upgrade it to a zero-g arena than it is to build a zero-g arena in the first place.
Fourth, and this is the one that I think needs the most discussion, if you get a new planet late game and it doesn't already have a lot of industry on it, it can take 100's of weeks to build an industrial sector, and currently, that may be your only option.
I can think of three solutions to this. One that has already been discussed is to simply zone the tile as industrial, and let the govenor build a basic factory, then upgrade it all the way to whatever is the high end.
Another idea that has had some discussion here is showing all of the Improvements. I don't think this is a general solution unless we add one modification: have a "Show all" checkbox on the planet screen by the build list so that it's easy to access if you want it.
The last idea I had, and one that I haven't seen discussed, is to have improvments start to give benefits before they're completed. Most of the improvements aren't going to be a single building, so the idea of an industrial sector slowly ramping up production makes sense. At the most generous, you could have an industrial sector, for example, start producing like a basic factory when enough work has been done on it to create a basic factory. It doesn't have to be that quick, you could say that you need 25-50% more work than a basic factory would take to get the same amount of work, that's just play balancing.
I like that last idea the best, as aside from game balancing, it doesn't change the UI in any way, resolves the issue at hand, and does so in a believable manner.
