Regardless of how it was that Julius Caesar rose to power, he never desired to destroy the republic or it's traditions. Even if he did wish to become dictator for life, he wasn't out to obliterate the senate or political institutions of Rome. He was trying to give some stability to a system that was unable to keep up with the pace of social changes wrought by it's own successes. It was the selfish act of his assassination that led to the true destruction of the republic IMO. The conspirators never really looked beyond their act to the consequences. What was their plan beyond assassination? Who stood to gain from this act? Who was to become the new leader of the Romans from among them? I doubt their motives were any more pure than Caesars. The powerful among the senate behind it just would not share power. What if Caesar had been allowed to live? Perhaps he would have ushered in a new form of Monarchical Republic-one more suited to the expanding empire.