I am sadly ignorant of much "serious" literature, and I only mention this for the ethical interest rather than the literary one.
But according to the famous Tom Stoppard in the Times, regarding an unpublished work that an author wanted burned after his death, there is a very simple answer: It’s perfectly straightforward: Nabokov wanted it burnt, so burn it.
That is probably the majority opinion. But this blog does not follow the majority. Tyler Cowen at Marginal Revolution offers a very different view. Dead people don't count in the social welfare function.
That is true. The degree to which we respect historical legacies is a decision for those who are currently alive. The question remains: do future people count in the social welfare function?