Long term repercussions of a surviving Bourbon Restoration?

[Noblesse Oblige]

Yep and bad news also for the Italian unification, because as you said as fellow Catholic countries , Austria and France will not tolerate that the Italian states ruled by their respective cadet branches (Two-Siciles, Modena, Parma, Tuscany) be eaten up by the Kingdom of Sardinia. Also ,French kings were the official "protectors" of the Papal States since its creation, so I can't see the Bourbon allowing Italian nationalists threaten his Holiness.

Now that I think about it, any national or cultural group unification in Europe will be strangled in the crib with a Franco-Austrian alliance (except maybe a united Scandinavia, and even then it assumes that the Oldenburg line still dies out and the Danes choose the Swedish monarch over the collateral Gluecksburg branch.) I don't see much radical changes in how Europe will look in a surviving Bourbon Restoration, at least for the first half or so of the 19th century.