I think this is precisely one of the things dealt with in the book "Military What Ifs". It maintains that none in the entourage of Hitler had anything like the demonic genius of Hitler. Hitler really was a singular world history altering person. Alas, with the worst consequences. Pity he didn't die. He should have. He was a very reckless soldier seeking danger.
Germany might have nonetheless turned authoritarian in the thirties, just like most European countries. Or might have not. In any case, without Hitler, we'd probably have got a traditionally conservative government, perhaps the restauration of monarchy. The German conservative revolutionaries might have had a field day (which later strongly influenced neocon ideology, btw). We'd have probably seen some border readjustments and finally the union of the Reich and Austria. At some point, there'd have then been a stronger shift to parliamentarism.
Today, Germany would be a parliamentarian monarchy, encompassing Austria and perhaps also the Sudetenland, Danzig, the Memel territory and have settled border disputes with Poland.
There'd probably be a European customs union, but not anything like the European Union.
In the thirties and fourties, the Soviet Union was the prime threat to the European order, but faced by an strong anti-Comintern its agression tapered out.
In the seventies and eighties colonial peoples increasingly demanded independence. Decolonialization started to kick in, partly sponsored by the Soviet Union (world revolution) and the USA (for "free trade"). However, to this day, parts of Africa are dominions and autonomous parts of the Union Francaise, the Commonwealth and "German Union".
Oh yeah, the US never got too involved in European affairs, but has been very active in the Western hemisphere and in the Far East. While the Economic Number One, Europe as a whole is ecomically stronger than the US.
English and German are the world's leading languages. Honourable mention goes to French.
Oh yeah, some time in the fifties the nuclear bomb was invented. Concerned with this development, the failed League of Nations (many had left the organization in the thirties) was substituted by the UN, which this time included the USA. The headquarters are in Geneva.
Ah well, that's my take!
