If the account in Act 1 about Caesar's coronation is plausible, then what does this say about Caesar?
Caesar was never coronated. Mark Antony had just won the laurel crown in the footrace at the Feast of Lupercal, and he offered it three times to Julius Caesar. This was a symbol that Antony believed that Caesar should be crowned king. Caesar knew the Roman people did not want a monarch after the last one was so horrible... that's why Rome did away with a monarchy. By refusing to accept a crown, Caesar won favor with the people. They saw his refusal as a demonstration of how he would not accept absolute power over them, and the Roman people cheered louder each time Caesar refused the crown. However, Casca (who happens to be the man reporting the details of the event to Cassius and Brutus) believes that Caesar was manipulating the people by refusing the crown. Casca also remarks that each time Caesar pushed the crown away, in his opinion, Caesar did so more reluctantly. If we take Casca's words as true, then this shows Caesar to be an ambitious, shrewd manipulator who knows how to play on the crowd's emotions. Indeed, his behavior in Act III when he states that he will not allow the banished Publius to return to Rome shows that Caesar has accepted that he has absolute power in spite of not being crowned king. Also, Decius Brutus had been able to lure Caesar to the Senate with the supposed rumor that the people were going to make Caesar their king that day.