I take two things from the Preface, maybe three. The first is that the difference between the Tractatus & PI is that in PI Wittgenstein has come to realize that human beings have lives as well as thoughts. The second impulse I take from Wittgenstein's almost pathologically modest Preface is that he conceives his task in poetic terms: "I should not like my writing to spare other people the trouble of thinking. But, if possible, to stimulate someone to thoughts of his own." [PI vi] That, too, is the task of poetry, at least since the beginning of the 19th c. & probably always, everywhere. Finally, it has been suggested by contemporary thinkers like George P. Landow that Wittgenstein would have been attracted by computer-enabled hypertext. There is a sense in which the Philosophical Investigations aspires to be a hypertext document, in which the various paragraphs could rub up against each other in different ways, could form & reform different "family relationships" as required (or desired) by the reader. So, perhaps we need to take a critical perspective on Wittgenstein's notion that a book of philosophy has a "natural order"; or to consider the possibility that the natural order might be one consisting of more than a simple narrative dimension.
Christopher Robinson & Joseph Duemer read Wittgenstein's Philosophical Investigations