What would have happend if instead of Prussia descivley defeating Austria while Italy took one blow after another, the roles of the two allies were reversed? What consqeunces does this have on both states, and how will this effect German nationalism? Would the war end on the same terms? Could Italy get better terms?
Ostost
Initially thoughts are:
a) Italy got a fairly decent result based on the Prussian success and I believe a late victory on their part. Advanced largely up to the mountains that are so easy for the Austrians to defend. It might get a little more but Italy was still pretty fragile at the time so if the Prussians have been badly mauled then the Italians might be facing strong Austrian reinforcements heading south.
b) If Prussia is badly defeated it is likely to lose Silesia at the least, which would be a major change in the balance of power. More to the point is it also defeated by the other German powers it fought? If so not only will Hanover survive and some others get stronger but they might get significantly stronger. [I.e. Saxony regaining the land lost in 1815 and possibly, most significantly, the Prussian Rhineland might be hived off. That would cripple Prussia as a potential unifier of Germany].
The impact would be to delay Germany unification, at the very least, and probably greatly change the future history of Europe and hence the world. Austria will stay the dominant power in Germany but be distracted by it's non-German territories. Also, even if it gains Silesia it won't have the territorial dominance over Germany that Prussia had post-1866 OTL, so it will not have the same degree of control. Prussia may be greatly weakened, reduced to a 2nd rate power or simply be still the 2nd power and in a position to threaten Austrian dominance in the near future.
Further afield France may still seem to be the greatest continental power but may try something in ~1870 and, unless the empire gets back-stabbed by a resentful Prussia or possibly Russia I would expect the Germans to win such an encounter but I suspect nothing like as clearly as Prussian led Germany did in OTL.
Steve