Levitsky, Ruth M. "'The Elements Were So Mix'd . . . "
PMLA, 88 (1973), 240-245.

Thesis: Levitsky begins with a quick review of the reactions of literary critics to Brutus. The earliest tended to idealize him, but in the middle of the twentieth century there was a reaction against this tendency. Levitsky intends to restore the balance. She points out that Brutus is not the perfect Stoic he would like to be—his passions sometimes get the better of him and his reason is imperfect—but he is still the noblest Roman of them all:
The patience and reliance on Providence which Brutus decides to reject would have made him more Christian than Stoic. But he was not and could not be Christian. What he could be Shakespeare made him: a Roman who stood out as more human than Caesar, more disciplined than Antony, and more pure-in-heart than any of his fellow conspirators.  (244)

Bottom Line: Persuasive and unsurprising.