Hindenburg dies in 1928?

The fact that Hindenburg dies at 81 in 1928 does not mean that Hitler will not become president a couple of year latter.

Who will be the new president if Hindenburg dies in 1928, acodring to this:

The Weimar constitution did not provide for a vice presidency. If the president died or left office prematurely a successor would be elected. During a temporary vacancy, or in the event that the president was "unavailable", the powers and functions of the presidency passed to the chancellor.

In 1928 Hermann Müller is the Chancellor of Germany leading a coalition made up of Social Democrats, Zentrum, DDP and DVP, so who would they pick as the new president of Germany.

Would a left leaning President even appoint Hitler Chancellor? Wilhelm Marx, had he won in 1925, would have been unlikely to do so. But, like i pointed out, the fatal hostility of the communists to the SDP prevents the labour movement successfully resisting Hitler.

If there is a fresh election in 1928, the President will serve until 1935, when Germany will be benefiting from the slow recovery that many nations did by then.

If Hindenburg dies in 1928 you have propably Wilhelm Marx (Zentrum), who originally lost in a narrow match 1925 against Hindenburg.
He was a major player in Weimar, even if not very well known in modern times.

His attitude was democratic, based on a balance between leftist (SPD) and rightwing (DDP, DVP) democratic parties.

in 1928 the NSDAP and with them Hitler was a factor, but not significant, it needed the depression of 1929-30 to let him grow big.
1928 the NSDAP gained 2,6% of the votes... so they are a zero-factor.

With Marx as Reichspräsident Hitler will not raise to power, becauser Marx was a democratic politican who "belived" in Weimar.

The depression kicks in, he will still try to keep the democratic (more or less) parties keep together against the communists and nazis.

With him Hitler will not be Chancelor, so the next elections in 33 mean that Hitlers Naziparty crashes... originally they were bankrupted by their extreme costly propaganda in 1932 that gained em lots of votes.. as usual for hitler he risked everything and - otl had huge luck. Here he will not have the vote of the Reichspräsident and his party crashes because they have no money left. Hugenberg and co had spent LOTS of money and expected payback - that will not come.

So either right wing terrorists kill the Reichspräsident or Hitler and the nazis fell back into the low digits or some failed coup by the SA... the Reichswehr was ready to kill them, they saw them as "swines they want to kill"... even with 3-400k men, without weapons the elite Reichswehr would have crushed such revolution easily. Doing that mean that Hitler is done for, cause it is one thing to do such "rebellion" in the early times, but in the late weimar phase - and against the Army it is a death sentence for his hopes.

With Marx living to 1946 OTL he could do 2 terms of 7 years, so he steer germany from 1928 to 1942. In this time weimar recovers, still fully rearm (there was no difference between communists and nazis in this part), if the french are weak they will look for austria - interesting side information: The crisis in germany and austria got from bad to terrible because the french acted in the way they did after German-austrian-tax-union-affair. Both wanted to prepare a unification, esp. france, but also poland and chechoslovakia were against. IN that crisis the death toll to fuel the banking crisis in germany and austria of 1931 (july 14. and 15) got out of control, some (not all) historicans think that this was the final path to destruction of german economy (compared to other european countries germany was hitted harder - these historicans say this was because of this behaviour).
So one could blame these german and austrian politicans who tried it, or - if you see it as their right to do it, the behaviour of france and later also UK did it.

So some interesting What-if could be, "What if germany and austria would not have tried to do the Deutsch-Österreichische Zollunion"...
less hit hard by the depression maybe avoid hitlers way to power?

Weimar will still have to do something about Memel, Danzig and the Corridor as they are itches that political parties of all stripes agreed needed to be scratched.

Sorry... i wasn´t 100% clear in my comment.
My opinion is this:
We give the nazis the "plus" (with heavy hearts, personally i want em all dead) that nothing else changes.
Hindenburg was a die-hard-monarchist who maybe disliked the nazis, but he HATED democracy. So Marx as President would not change that, but still would propably be more pro democracy as Hindenburg. As much as i could found out about him, he had no ties or positive reflections on the nazis. 

So all other elections stay the same - the nazis win in november32, but Marx will NOT, repeat NOT make Hitler Chancellor. That is - for any "democratic" President a no-go.
So either he rule similar to Hindenburgs dicatorship of "presidial chancellors" against the parliament - and would still do that longer as january 1933, or he would find a better government that include a majority of democratic parties. Both is - compared to OTL an improvement.


So with Marx as President we do not get Hitler as "legal elected/announced" Chancellor and so no faked march33 elections. 
But nov33 allready saw the decline of Hitler, here the Hugenberg-Complex will no longer put money into a "dead horse"...  in the same time the internal problems of the nazis would tear em apart.

On one side the leftists (Strasser and Co), on the other the ultra right wingers (with naturally Hitler beeing the major player), then you have the SA with Röhm who wanted his "civil war against the hated army"...

It is a powder keg ready to explode.

So Hitler can do these things
a.) try to still gain democratic power... for that he need to wait till Marx is out of power - or try to kill him and be himself President (As OTL tried and lost against Hindenburg)
That is highly risky because if the kiling fails and they catch the killers things could blow up. Esp. with a more conservative president, who also do not suit as a scapegoat (no jewish, or something "bad" in the eyes of the right wing assholes)
b.) try to gain power with brutal force - basically let Röhm do his putsch.
We know from the structures of the SA, the bad organisation and the preparations of the Reichswehr that this would end in a bloodbath with loopside casulties (20:1 or worse) against the SA.

Both scenarios are bad (for the nazis) and have no real succsess.

With a recovery of the economics Hitlers positive impact (promising jobs and food) onto the hard hit society will be even more reduced.

So- with Marx as president in 1928 - after an election - you basically avoid Hitler personally and the nazis till 1935, at this date Hitler is either dead, on the run (hunted for starting a civil war), imprisoned. The chance for a raise of the nazis as OTL would be destroyed.