It might be nice if laws -- or at least perhaps the frequently-applied and/or controversial ones -- had to have associated metrics with them before they're approved for merge into the legal code. Then we could get into longer-term nitpicking about what are fair and desirable metrics (because, ideally, they'd become a model of what the population more-or-less agrees that they want) and also we could git blame/bisect to see the legal changes that produced effective results, and view the commit history to discover the pressures or politics that resulted in the enactment of problematic changes. To some extent I think this probably already exists -- the forking of British legal code from the EU is an example -- I'm just not aware of the tooling and processes that are used to measure results, performs diffs, cherry-pick or revert, and so on.