We can toss back and forth which great man wins this civil war or that. But it doesn't matter who wins, if the fundamental structure of the Republic is not reformed, once we enter in the post-Marian era, military force becomes far too valuable a means of enacting political change within the system.
I maintain, as I have for some time, that after Marius, your best bet for prolonging the Republic is to reform the Comitia Centuriata, so that its composition better reflects the composition of the army. Once the land requirements were waived, Rome had a mass of highly trained soldiers who's voice in the government was orders of magnitudes smaller than those of previous generations' legions.