I suspect that any worthwhile exploration of these deep questions about living requires going beyond abstract discussions to the vivid presentation of possibilities. If readers are to be prompted to serious examination of their lives, anatomy isn't enough. We have to be stimulated to imagine, in some detail, what it would be like to live in particular ways.

Mann was less interested, I think, in constructing any kind of "portrait of an age" than he was in delineating an individual consciousness in which profound struggles about identity and direction arise - struggles that Mann himself had not only reflected on but felt keenly. Visconti takes up this central focus of the novella, but he couples it with a more social perspective.

Consider the different narrative styles within the story, and the glee with which the "moralistic narrator" celebrates Aschenbach's fall - maybe, then, this is a hostile verdict and the international fame is warranted after all (given that Mann modeled his protagonist so closely on himself, it would be quite odd if he had intended Aschenbach's literary inferiority to be a fixed part of the interpretation).

Read Mann's notes, which contain precise accounts of cholera and its symptoms, and observe how careful he is throughout his fiction in getting medical details straight - then you might begin to wonder whether cholera is the only candidate for the cause of Aschenbach's death. What results from this, I think, is a deeper appreciation of Mann's brilliance in keeping so many possibilities in play. The ambiguity is even more artful than people have realized.

I'm very suspicious of the idea of a "final theory" in natural science, and the thought of a complete system of ethical rules seems even more dubious.

Klaus Mann saw very clearly how different was his own (more liberated) form of homosexuality from the same-sex attractions of his father - and that is reiterated in TM's diary queries about "how two men can sleep together".

I think the tone of mockery Heller finds is a part of Mann's irony, but only a part - a brilliant further touch consists in juxtaposing perspectives so that we're led to wonder whether the mockery itself is the last word.