"If no one is charged with $crime for n years, it goes away unless explicitly renewed" would fix some of the weirder laws still on the books, but by definition wouldn't really change much.
No, it wouldn't fix anything, but it would result it annoying periodic pro forma charges being filed.
When you take a measure and tie a control function to it, you make it a target. When you do that, Goodhart’s law applies, and when the specific connection is as simple as “maintaining a criminal law requires charging someone under it with at least X frequency”, the failure mode is obvious.