Is Julius Caesar’s death justified?

One could argue that Julius Caesar's death was not justified because there is little evidence of his ambitious nature and his assassination only leads to the ascension of Octavius, who ends up becoming Rome's emperor. Brutus struggles with his decision to join the conspirators because he is not sure that Caesar wishes to rule Rome as a monarch. In act 2, scene 1, Brutus contemplates assassinating Caesar and even admits,

"And, to speak truth of Caesar,
I have not known when his affections swayed
More than his reason." (Shakespeare, 2.1.19-21)

However, Brutus surmises that assassinating Caesar will ultimately prevent him from disbanding the Republic and becoming Rome's emperor. It is also important to note that even if Caesar does wish to rule as a monarch, it is not certain that he would become a tyrant. Caesar could easily become a just, morally upright ruler if he were to become emperor.
Unfortunately, Brutus is swayed by Cassius into joining the conspirators and ends up participating in Caesar's murder. Caesar's death causes political and social upheaval, which allows Octavius to become Rome's emperor after defeating Brutus and Cassius's troops in battle. Overall, one can argue that Caesar's death was not justified because no one knows what type of ruler Caesar would become if he were ambitious enough to disband the Republic. Also, Octavius eventually becoming Rome's emperor is evidence that the assassination did not save the Republic or protect the populace from being ruled by a monarch.