Bump, for instance, might repartition have been on the table if an alternate world war one occurred much earlier, like in the 19th century.
In OTL Clemenceau and other French nationalists noted that dismemberment of Germany was never on the table in the WWI that started in 1914 and certainly not at the Versailles Conference. Despite plans for annexations & indemnities at Germany's expense, the continued existence of a mostly sovereign Germany was taken for granted by all.
But what if an alt-WWI happened earlier, or if despite Bismarck's best efforts, the "nightmare of coalitions" occurred and Germany were defeated by a coalition of other powers within the same generation or so of when the 2nd Reich was established? Might the constituent states of the Reich be seen as natural breakpoints?
For specific PoDs I have in mind a couple:
a) 1875 "war in sight" crisis leads to an actual war that Germany loses.
b) The Bosnian/Bulgarian Crises of 1876 turn into a general European war, and Germany ends up on the losing side.
c) Germany ends up in foreign war and is defeated while the Kulturkampf and campaign against ultramontanism is still going on. I forget the exact periodization.
d) A Boulangist France and irate Imperial Russia defeat Germany in a war.
Might any of these lead to 2nd Reich fragmentation, or would a core "Germany" be seen as a natural European fixture as early as the 1870s and 1880s?
Feel free to insert other ideas of your own.