Don''t think Cassius would have objected to that one bit.
The "too ambitious" was the perceived intention of JC to make himself King of Rome, anathema for many centuries to Republicans.
Which he probably intended, though not perhaps specifically under that title. Making himself Dictator for Life was pretty much the same thing.
His nephew of course actually accomplished this, but managed to disguise the autocracy with a veneer of republicanism enough to avoid his uncle's fate.
Cassius was just a murdering scumbag, and got what he deserved. That’s more than can be said for the Gracchi, who were beaten to death by their fellow Senators and their bodies thrown into the Tiber. Caesar was a reformer, Cassius et al were elitist reactionaries.