Had Napoloen the Third tryed replicating his uncles conquests with just france or an alliance with another great power like austria.what would have happen to Europe and france .
Swift coalition against him, deposition after one or two campaigns.
Napoleon III, if he is remembered fondly, is remembered for his domestic, diplomatic, and imperial achievements, albeit with the Maximilian fiasco. That could have turned out better if he chose a hardcore conservative leader with a drive and talent for crushing rebellion since Maximilian seemed to want peace between Mexicans and kept offering peace terms towards an enemy that only saw such actions as a sign of weakness rather than an open desire for reconciliation; or Napoleon found a way to kill off Benito Juarez around which opposition to Maximilian was centered and the entire Republic in Rebellion against the Empire had true legitimacy.
Napoleon could have led France into a new direction, and that is where the wealth of his alternate history credibility can be stocked. Him being Nappy 2.0 will result in a failure of unspeakable proportions. He wasn't all that spectacular of a general. Competent under the proper circumstances, but his power ultimately resides in political charisma. A great deal of that is owed to his name.