Liberal Germany, Independent Hungary, United Italy, 1848

[Homer]

Russian hostility might be a bonus: it pinpoints at a common foe, and would be a factor of unity.
The "disputed lands" were there in OTL too (and the German/Italian unifications did not solve the issue). Maybe this time around some compromise solution might be achieved on a cantonal basis.
Hungary is a problem, I agree. But again, the progress of liberalism might simplify the research of a solution

Russian intervention was desastrous OTL, since the Russians were clearly anti-revolutionary.
I think French intervention could be much better: French intervention would directly hit the Southern German states AND Prussia, not Prussia alone as Russian intervention would, thus the"common sense" of the new Empire would be deepened. and united Italy.
Maybe if the French start by occupying Rome to protect the Papal States and only then fight on the Rhine, that would part their troops.

 

[LordKalvan]

Russian intervention dates 1849, after the substantial failure of the revolution in western Europe: the Habsburg empire has put a lid over the unrest in Italy, Austria and Bohemia; only Hungary is still rebellious. The king of Prussia has refused the imperial crown of Germany. Louis Napoleon has been elected president in France with a landslide victory. The liberal revolution in Italy has also substantially failed, even if there will be another go next year.

My scenario would be quite different: Germany would be a liberal monarchy; the Habsburgs have gone (to Russia?); Hungary has moved pretty earlier than they did in OTL; the liberal revolution has triumphed in Italy too (and also the Bourbons of Southern Italy are in exile, probably in Spain); the pope is virtually a prisoner in Rome. These events would have a deep effect over the Directory in France: Louis Napoleon was never a driving force until the presidential elections of December 1848 (where he won by a landslide, but on the strength of the rural vote and the name "Bonaparte"); a more successful liberal revolution all over Europe would have effects in France too, and result in a more leftist directory. IMHO, the events in 1848 were too fast for the Russians to react on time: by August/September 1848 the revolution would be triumphant, and the Russian army would be still mobilising (I'd anticipate that also the revolt in Poland would be much more strong). The best that the Russians can do is prepare for the spring 1849; they would be alone, though, in opposing the armies of the liberal states.
Under these hypothesis, the Russian menace would do wonders to unify the liberals all over Europe (and it is quite possible that Louis Napoleon goes back to obscurity).