Rather than taking a defeatist attitude that the problems from tech trade cannot be solved, I'd like to just out a "strawman" idea -- as we sometimes stay in the biz.
What if you can trade military techs, productivity techs, construction techs? And, on the other hand, you can't trade social techs, or governments, or religious techs, or even commercial techs.
The idea being that you can teach a primitive civilization how to manage nuclear weapons, but you can't teach them to be free.
Plus if you add this to branching dilemmas... (e.g.: Taking one branch gets you tech A, then B, then C, then D; another branch exists that gets you D and A right away, but B and C aren't in that branch and thus you miss out on those techs until later.) -- then trading for a military tech "too soon", without going through the social techs and government techs that would democratize your society more, you would miss out on the chance to really progress *socially*.
Damn, I have to be able to find a better way to explain this. Does anybody know what I'm talking about? I'm trying to explain how you can a nation who discovered Nuclear weapons in a democratic society, and another nation who has Nuclear weapons but seems unable to become democratic (even if they know what democracy is).