A prominent Alternate History cliché: If the POD is before 1859, or at least long enough before 1859, in any eurocentric timeline Italy will not unite. Ever. Instead, the Italian states will continue to exist as single states, with apparently nationalism never even coming up again for some miraculous reason. It, like this article, is the exact Italian equivalent to the Disunited Germany cliché.
Like the German cliche, the reasons are manifold, but less intensive: The reason that a disunited Italy is geopolitically more interesting applies fully. The reasons of nostalgia about and “loyalty” to some of the old Italian states apply rather less so. It is also hard to wank other countries at Italy's expense. Mostly, the Disunited Italy cliché seems to exist due to a general historical nostalgia for the old order.
Of course, this cliche overlooks that nationalism was a force in Italy in the 19th century, just like everywhere else in Europe, and before the Risorgimento it was tied with democracy. It is unlikely the states could have continued to exist independently without a strong nationalist-democratic opposition. Also, the continued existence of the Papal State is not unproblematic, as it is likely that in a progressing Europe its acceptance would continuously decline, in its own population and by other states. Of course, one could imagine a collection of authoritarian, troubled states in southern Central Europe, but the cliche also usually calls for the states to progress as normal.
Susano is the member who gets most irritated about this cliche, one of the most widespread and most accepted cliches in Alternate History, mostly because of its connection to the German case.