The problem with not having a jury is no one ever gets a chance to then be a final arbiter on an unjust law. You just have robots applying a tickbox test.
Remember Clive Ponting ? No magistrate or judge would have acquitted him. It took 12 random people to say "hang on, this is bollocks".
Once you lose that, you lose the last chance the public have of peacefully demonstrating to the establishment how wrong they are.
Lady Chatterlys Lover ? Decided by a panel of magistrates and a judge ? Would have been a guilty. And wives and servants would not have been allowed to read it.
I would be curious to know how non-jury judicial systems allow for something like jury nullification. If indeed they do.
Computer says: guilty.