First pass at POD list
Okay, here is my first pass at a rough list of PODs that might help a recognizably Weimar Republic survive (at least past its dissolution in OTL, we still need to work out the 1930s on).
First, if we decide to go with some pre-Weimar PODs (not my preference but to be fair lets examine them)-
WWI -Hitler dies in the trenches (but would his absence be enough?)
- Lenin doesn't make it to Russia (dies, never goes, whatever)
-Kerenski makes peace with Germany (not sure how this really helps)
-Richtoven lives (cutting into Goering's cache, may undermine Nazis later)
-Slightly different Constitution drafted at Weimar with either a run-off provision for the presidential elections and/or no or weakened emergency powers.
-Slightly better terms at Versailles (not certain how this would come about)
Okay, now for the post Weimar Constitution PODs
-No Kapp Putsch and no General Strike (which perhaps inspired Cuno to use strikes in the Ruhrkampf).
-Paul Lettow-Vorbeck gets a cold in 1920, not able to support the Kapp Putsch, will rise in the Reichswehr in place of Kurt von Schleicher, becomes close advisor to Hindenburg in his stead, leading to no von Papen, no lifting of ban on paramilitary dress and orgs, no legitimization of the Nazis during the early 1930s.
-No Ruhrkampf (not certain how to avoid)
-Cuno pulls off a political victory early in the Ruhrkampf (not sure how)
-Stresemann replaces Cuno much earlier, ending the Ruhrkampf and nipping hyperinflation in the bud (has a proven OTL record for his ability to do both, but now it is earlier and thus less damage to the Republic).
- Earlier and/or more decrease in reparations (likely due to several of the other PODs mentioned, or possibly due to US easing war debt on entente nations (don't see why))
-Harder crack down on Beer Hall Putsch or no Beer Hall Putsch, Stresemann Chancellory does not fall.
-1923 Ernst Thalmann, leader in the Communist party, is successfully assassinated, and thus not a candidate in 1925 and the Communists throw the election in the second round to the Weimar Coalition candidate as per Comintern instructions).
-1925 Friedrich Ebert seeks medical assistance earlier and undergoes successful appendectomy, survives to win reelection in 1926 and serves at least to the next election in 1933.
-1925 election has different result (mainly no Hindenburg victory) with any of the following winning:
*Otto Braun (becomes Weimar Coalition candidate, Communists throw in support)
*Wilhelm Marx (Weimar Coalition victory due to Communist support)
*Gustav Stresemann (runs, maybe from earlier POD still chancellor)
*Karl Jarres wins on the second ballot (Stresemann more active in opposing Hindenburg or Hindenburg declines nomination)
-Mid 1920s reform of military to make a little less right wing (unlikely)
-Mid 1920s Soviet invasion of Poland, West starts to build up Germany as an anti-communist buffer. (unlikely invasion)
-Josef Wirth does better (can't remember how or why, anyone?
-1929 No or lessened Great Depression (anyone? I've got suggestion of the US being involved in the League of Nations helping (doubt) and a Keynesian approach to liquidity replacing Hoover's deflationary policies (don't understand or know how this would happen).
-1929 Paul Lettow-Vorbeck more successful in building opposition to the Nazis within the right wing of German politics (don't know how, he tried and failed in OTL)
-Early 1930s Muller's government holds on.
-Early 1930s Weimar Republic pulls off an Anschluss with Austria, gains street cred with pan-Germanists.
-Bruning not undermined by Schleicher, manages to pull off getting the reparations virtually dropped (which actually happened in OTL due in part to Bruning's policies, but Nazis took the credit).
-No cut in the Technische Notdienst (a state paid voluntary civilian emergency unit used to keep open important facilities during strikes, likely should be the result of a POD rather than a POD itself)
-No end to the Decree banning paramilitary uniforms and organizations (again, likely the result of a POD rather than a POD itself).
-Schleicher doesn't support von Papen or bring him to the attention of Hindenburg (thus no von Papen chancellory and no undermining of a Schleicher chancellory if he does take office).
-No Hitler (or Nazis) in the chancellory (likely due to one of these earlier PODs)
Some possible leaders (likely given the chance due to one of these earlier PODs) for the 1930s, mostly popular mayors of big cities.
*Hans Luthor (Essen)
*Karl Lautenschlager (Stuttgart)
*Konrad Adenauer (Cologne, very attractive prospect since he did well as Chancellor of the Federal Republiic of Germany for decades)
*Goerdeler (Dresden)
*Scharnagl (Munich)
Okay, that is my rough take from the many comments made thus far. See what y'all think and what else we need to do.