I think its important to understand that Caesar was a great man who filled a gap in history perfectly. If not for Caesar, Rome would've followed a similar, yet decidedly alternate path.
Some conjecture...
Without Caesar, Crassus and Pompey would've never become reluctant allies. They very well may have developed a rivalry far more serious than it already was. Was civil war inevitable? Maybe not. Without Caesar's campaigns in Gaul perhaps Crassus didn't need to seek glory in Parthia.
But I am getting too far ahead. Without Caesar, Pompey's veterans probably never get settled. What does Pompey do with an large army that the Senate refuses to grant retirement benefits? Perhaps Pompey becomes another Sulla. Perhaps men like Clodius become even more dangerous, though I doubt that a tribune demigod could ever have been more than a major disturbance. Cato, without Caesar to thwart him, may have developed truly into the greatest Republican statesmen ever, and saved the Republic.
However, I doubt it. In the late Republic statesmenship never won, the men best generals and the best armies did. Alas, the Republic was doomed with or without Caesar.