jeejeep
qwertyuiop
The upgrade costs are probably somewhat necessary, but that doesn't mean I have to like it. I think it would probably be an improvement if the AI had to pay slightly more to upgrade, so that maybe they could only upgrade about half their units immediatly and would have to go to 0% research for a few turns if they wanted to upgrade the rest. Instead of just letting them upgrade units basically for free, Firaxis should be able to work with the AI until it can weigh the costs and benefits of losing research for a few turns to upgrade.