That would require you to amend the charter. That may be bigger than what you thought you were biting off with this question.
In some cases, there's a requirement for juries unless the crown consents to there not being a jury. Many people elect to have a trial by judge alone. Many people would elect to have a trial by judge alone even in those cases where it's required. If you're looking to limit the number of jury trials, one thing you could do is to allow an election to be done in every case regardless of what the offence is. We have section 469 of the Criminal Code which requires there to be a jury unless the crown consents otherwise. You could just do away with that and have an election in every case if you wanted to limit the number of jury trials.
I don't know if there's research on trends in the number of jury trials or not. I think it varies from jurisdiction to jurisdiction.