Alright it seems these things need to happen:
1. Either Prussia gets a bigger slice of Poland or Germany defeats Russia in a war. Maybe Russia tries to prevent Germany from uniting and suffers the role that in OTL was France.
2. No Lorraine-Alsace war. How about the French unable to meddle in German affairs when it´s about to be united due to either: Revolution, civil war or a war with someone else. (Perhaps Britain, wouldn´t want to be in a war both with Britain and Germany at the same time if I was France
).
3. Ireland apparently needs a much earlier revolution, and it needs to be so big that the British give in. (How about French support like the colonies had
).
4. Italy defeats Austria and gets the Tyrols, perhaps Swiss allying with Austria
But what would the POD be for all this.