Hitler slips and breaks his neck in 1928. The different right-wing parties remain divided. The political climate is heated until 1934/35.
Then it becomes clear to everybody that the economic situation is getting better. Extremist parties on both sides lose popular support and the German democracy somehow survives.
Alternatively: Riots and brawls between extremist get out of hand and anti-democratic forces/forces critical of democracy in the government (von Papen etc) declare marshall law and Germany is transformed into a system with more similarities to the old Wilhelmine system. Cencorship of the press is reintroduced, stuff like that. Some extremist parties are outlawed and members are arrested. The army cracks down any larger riots caused by this.
Eventually the situation calms down, marshall law is disbanded and Germany is now a somewhat authoritarian conservative democracy where extremist parties are not welcome.
In both cases völkisch and communist view remain among some parts of the populace, though.
Germany keeps subtly breaking the rules of Versailles and the Entente powers keep tolerating it.
Pan-Germanism is still around and without extremists in power, Austria joining Germany remains a possibility in the future(though I don't know if the Austria leadership is willing).
Eventually, some kind of treaty about the usage of Danzig has to be found. I don't see the possibility for war there, with rational persons in power. Hopefully.
Remilitarisation of the Rhineland will likely only happen by treaty.
Without Nazi Germany, Stalin keeps a low profile and doesn't try anything daring in Poland, because he knows that would only force Poland, Germany, France, etc in one camp against him.
Without a war in Europe, Japan can't be as opportunistic as in OTL and will not try to take the European colonies. And it will probably not dare to attack the US as well. Not too sure on this one though.
In the long run, Japan will not be able to hold on to China and it will have to give up large parts of it. It will probably keep some cities, I guess.
Korea be eventually japanized.
The US will stay more isolationist. The Civil Right Movement will be delayed until the 80s.
Decolonisation will be delayed as well.
Racism is not dicredited.
The atomic bomb will be discovered by one of the great powers in the 60s or 70s simply because they can.
Problem is, as long as there is no mutually assured destruction and to a lesser degree as long as Europe didn't suffer the devastation of terror bombing, nations will be more likely to go to war for whatever reasons.
A war might ventually break out, out of spite. Terror bombings (and if this war breaks out after the creation of the atom bomb, nuclear bombing, as well) will be used in such a war. It will be unpleasant. After that, people will be less likely to go to war, i'd say.
Israel will not come into existence. If Britain creates it anyway for whatever reasons it will not as many (European) Jews as it did IOTL after the Shoa. If some Pan-Arab consensciousness appears in the process of (delayed) decolonisation, it will probably be swallowed by one of the surrounding nations.
Opinions?