Yes, I know this appears to be a rather odd combination but hear me out...
In "History of Rome" by Theodore Mommsen, he states that Marius was never a populist so to speak(he was never exceptionally close to the proletariat, but was just of a just and fair nature), but due to being rather "coarse" and despised by the more refined aristocracy, he was pushed forward as the champion of the Populares.
But in the same book as above, it states that Marius was not a competent politician, and therefore he tried to take a middle path between the old aristocratic families, the moneyed elite/merchants and the proletariat and led to the destruction of his movement.
However, I dispute this statement.
Gracchus, especially Tiberius, was a hardliner reformer. Of course in the latter stages he did so in order to gain protection from the elite he had challenged. But his hardline reforms actually led to death and an even more divided republic.
So... Moderate reforms or hardline diehards? Where do we draw the line? Any other examples in Roman history?