After the Armistice? That's
hard. Everything that was a real flashpoint in Europe, it seems to me, arose from rival interests that were quite simply impossible to reconcile. It was impossible to avoid these terms coming under attack once the defeated parties returned to existence as normal powers. The issues where there was no fundamental contradiction in expectations (eg, Schleswig-Holstein, thanks to the conspicuous reasonableness of the Danes; Alsace, which everyone had known was inevitable since 1914) weren't hotspots.
Personally, I don't believe that the OTL treaty made another war, or German facism, inevitable and I think it was just about the best that could have been arrived at given the circumstances. Handwaving just
how they're implemented, here are terms which I think are semi-plausible after the Armistice (most of them would not have happened, but they don't actual entail sacrificing any Entente strategic interests) and could reduce German grievance:
- A less in-your-face approach to war guilt. E.H.Carr said something very pithy about that, if I could just find it. Perhaps acknowledging that the victorious powers are innocent, which allows Austria-Hungary and Russia to be left as elephants in the corner. This view is hardly accurate (I consider everybody "guilty" to varying dgerees, and the whole blame-game a rather petty exercise given the circumstances of 1914), of course, but the idea is to make Germany feel less persecuted.
- A more manageable programme of reparations. I'll admit an embarrasing ignorance of the economic side to the whole issue, but my gut feeling is that that could have been done better.
- A formal plebiscite for Alsace. It's not like France wouldn't win.
- No silly-buggers about the Memelgebiet.
- Less flagrant abuse of the Hungarians. I am put in a somewhat tortured position by being a Slavophile who likes both Romanians and Magyars, but there were some things that Hungary really should have kept: Satu Mare, Arad, Oradea, and most of the first Vienna award, for instance.
I don't see what good Italian Dalmatia does anyone. I've always been slightly dubious of whether a democracy with such major structural problems as Italy can be saved by a few more Croats to oppress, and if we want to avoid war, well; fascist Italy by itself is a sane power and not going to start a European land war, whereas giving the Italians big chunks of rebellious Yugoslavs is sure to create a hotspot. If Italy blunders into a war with the Yugoslavs (who will have even more motivation to awkwardly unite), Germany and Austria will start to look longingly at what they've lost, and France and Britain are unlikely to run to put that fire out.
Leaving the authorised PoD, I think Russia still in the game (while it implies plentiful problems
for Russia) is a pretty good starting point, because it removes some of the fundamental contradictions in the German-Polish border. Russia will want Great Poland, but has no particular desire for sea-access or a desperate need to buff up its industrial potential. And it's obviously a state that you can't attack, wage trade-war against, etcetera so easily as Poland; nor does it have any motivation to chase away valuable German human capital (although I think there'd be some migration from the Poznan region anyway).
Preserving the Hapsburg monarchy for the time being also addresses several problems: Anschluss, which was neither acceptable nor in the long time avoidable, can be returned to the back-burner; there's no Sudetenland problem (yet, anyway); Croatia and Serbia aren't obliged to insert a square peg into a round hole, balance Slovenia on top, and attempt to make a functioning state of it. Not terribly good news for Transylvanians and especially Slovaks, but the Hungarian-Slovak and Hungarian-Romanian conflicts are frankly impossible to solve fairly by that point.
So, let's say neutral Ottomans (good primary PoD for an early Entente victory, and makes a more stable and ordered post-war world in itself). The Entente wins early on, Austria is preserved as a state but loses a variety of peripheral territories (Galicia, Serbian lands). I'm not sure whether Italian and Romanian involvement makes the situation more or less stable and sustainable.
Now, Russia is on the path for an unfortunate accident, but I can't exactly see it being worse than OTL.