I think civ 3 should have prereq for building stuff. For instance no tanks should be able to be built if you don't have at least a factory in the city. No spaceship parts should be built in a city if you don't have at least manufactoring plant in a city. I hate playing to the end with other players who build 50 size 2 and 3 cities with no improvements then send caravans from 2 size 20 cities out to other civs to get a 2000 cash bonus per caravan. Then when the time comes they just buy a spaceship in one turn.
It's not a new request, and I must agree it has some good point.
Another solution should be to reduce the power of any "hurry up by money" on production. I already wrote about this on other posts, so better I don't repeat myself to avoid annoying you
I agree with this idea to a point. There should only be certain improvements required to build
certain units in the MODERN AGE or perhaps even the INDUSTRIAL AGE.