That's very hard to measure. ISTM that in international relations things tend to either muddle along rather badly with gradual incremental improvements that roughly track economic growth, but when they go bad (ie resulting in war or massive political change) they tend to do so quickly and catastrophically (in the sense of a major discontinuity rather than mere badness, although more often than not it's bad).

And while I share your reservations about the US as a global hyperpower whose policing of international relations can frequently result in backlash (not unlike its internal policing culture...) I'm also inclined to look back at the era prior to the formation of the US and note that when there's no clearly dominant actor on the scene you have endemic peer conflict.

the increasing flow of information is forcing us to act rationally

I'm more pessimistic than you about this. It is easier then ever to make rational decisions thanks to all that information and accumulated insight, and I do think the US is maturing as a society. But there's an argument that irrational political behavior is rationally rewarding for voters who know they have very little influence over the political process and take their vote as an opportunity to express their disgruntlement through perversity. Bryan Caplan has a very good book about this called The Myth of the Rational Voter, if you like economics.