In a system without jury trials, it would be more difficult for defendants to be acquitted of the charges against them. This is because the system would be more of a closed system, an insiders' club. This would build systems of trust and mutual understanding that would lead to more convictions.
If judges were the only ones who determined guilt or innocence, there would be more convictions. Judges and prosecutors work with one another every day because of the nature of the system. They get to know one another better than they get to know the more numerous defense attorneys. If there were no juries, the judges would naturally have more sympathy for the prosecutors because they would know them.
The judges would also be more skeptical of defendants' stories. Juries are less jaded than judges and are more likely to believe what defendants say.
Overall, then, a system with bench trials only would work to the benefit of prosecutors.