You probably know this by now, but what the heck. I don't think EA as a whole is RCT-only. GiveWell is, AFAIK, very randomista. But there are other EA-affiliated organizations that are not as randomista as GiveWell, notably Open Philanthropy and anything with a more x-risk or long-termist focus.

Thank you for challenging the question's assumption, Mr. Miller. Your points notwithstanding, I think you under-appreciate what we have, even though it could have been much better. I hope the tools that I envision would someday help clarify convincingly why not all regimes are essentially the same for human well-being.

• cons
  • if we understood regime transitions better, then so would pro-authoritarian actors, and they would be better able to protect and promote authoritarian regimes.
    • for example, if we discover that women's rights were a long-term driver of democratization, an authoritarian regime may choose to keep women repressed to preserve its grip on power. Without this knowledge, the authoritarian regime might welcome women's rights, and eventually liberalize as a result.
• pros
  • if we understood regime transitions better, we would be better equipped to safeguard, strengthen and possibly even promote the development of liberal democracy where it does not exist.

Those are first-order arguments, and they are symmetric. Second-order arguments might consider whether the pro-democracy or the authoritarian side would have more use for this knowledge. 

• In an authoritarian regime, the government has many more actions it can take to shape developments, and a greater command of resources, than pro-democracy forces. So a highly-detailed understanding of regime transitions is likely to solidify authoritarian regimes.
• in a liberal democracy, 
  • the pro-democracy forces may be roughly on par or even stronger than those promoting authoritarianism. 
  • power-seeking actors are shaped by an evolutionary competition for political power, and so learn by trial and error how to gain and secure political power.
  • There is a certain asymmetry between the competitive dynamics that shape pro-democracy and authoritarian agents. I will hopefully develop this idea further in my next comment.