Which countries would benefit most from an American brain drain?

China. China. China. The answer is China.

Honest question, what would be gained by moving from America to China? Their government is by nearly all measures less tolerant, less free, less friendly to foreigners, more racist, and at least as morally evil, but probably more so considering their treatment of the Uyghurs and other minority populations.

At least in America if you’re not a fan of the Trump administration we’ll have another leader in a couple years. You can’t say the same for China.

Stability. You said it yourself:

> we’ll have another leader in a couple years

Depending on how you look at it, it could be seen as a disadvantage. China's policies are generally long-term and stable.