This is a challenging question. Winners in history do not allow negative protrayals to survive. For this reason, in order to find weaknesses in Octavius, we will need to read ancient literature carefully. When we do this, a few weaknesses emerge.
First, Octavius was not a very good general. According to the historical sources, he defeated almost no one. Marcus Agrippa, his general was the great military man who defeated the foes of Octavius. This is a considerable weakness is a society that prizes martial valor and victory.
Second, Octavius was weak constitutionally. He often got sick and at one point almost nearly died. If this happened, the course of Roman history may have looked different.
Third, Octavius had difficulties with succession issues. So, in the end, he adopted Tiberius, who was a hated emperor. The assumption here is that great leadership should have greater foresight.
Finally, Octavius was prone to pride, who could be distasteful to many.