> Modern law is supposed to be open, so that anyone can read it.

This is already not the case -- at least in a common law system like is practiced in most of the US (and other Anglo-Saxon countries). Even if a normal person can understand the legalese, they can't be expected to know about the history of court cases that have reinterpreted and redefined the laws in question in various ways.

Why else would it take so much training to become a lawyer?