We should welcome more precise law enforcement. Imperfect enforcement is too easy for law enforcement officers to turn into selective enforcement. By choosing who to go after, law enforcement gets the unearned power to change the law however they want, enforcing unwritten rules of their choosing. Having law enforcement make the laws is bad.

The big caveat, though, is that when enforcement becomes more accurate, the rules and penalties need to change. As you point out, a rigidly enforced law is very different from one that is less rigorously enforced. You are right that there is very little recognition of this. The law is difficult to change by design, but it may soon have to change faster than it has in the past, and it's not clear how or if that can happen. Historically, it seems like the only way rapid governmental change happens is by violent revolution, and I would rather not live in a time of violent revolution...

The problem with precise law enforcement is that the legal system is incredibly complex. There's a tagline that ‘everybody's a criminal’; I don't know if that's necessarily true but I do definitely believe that a large number of ‘innocent’ people are criminals (by the letter of the law) without their knowledge. Because we usually only bother to prosecute crimes if some obvious harm has been done this doesn't cause a lot of damage in practice (though it can be abused), but if you start enforcing the letter of every law precisely it suddenly becomes the obligation of every citizen to know every law — in a de facto way, rather than just the de jure way we currently have as a consequence of ‘ignorance of the law is no excuse’. So an increase of precision in law enforcement must be preceded by a drastic simplification of the law itself — not a bad thing by any means, but also not an easy (or, perhaps, possible) task.