1) The issue is that violence is a poor metric for progress. Pinker has made it clear that the description of declining violence is done in order to describe the improvement of the human plight, as most succinctly crystallized in the title of his first work on the point, and the overarching research thesis of his second. The structure of his first argument also points to this: violence has decreased, and all of the reasons have to do with humanity getting better, smarter and more empathetic. Here I suggest that in order to make that claim, broadly, we need to understand what violence is, and why its reduction may actually be a symptom of things getting worse for people. I am not the only one to make this distinction. Many groups advocating for historical 'have-nots' make the same counterpoint in reaction to Pinker's work.
2) With regards to the legal system, the issue is tremendously worse than it used to be. There was a time when "normal people" had better access to justice - the fact that you even need to ask this question should cause readers to pause and reflect upon what that means for the system.
The legal system, like measures of international violence, have social purposes - this is where Pinker's arguments fall flat to me. Think of them as pressure release valves. If the negative causal force (i.e. Conflict) causing those systems to need to act aren't actually being reduced, yet the system is systemically reacting less and less to the stimuli it is receiving, it is akin to a server reporting that it is A+ Okay and only under 25% load, but ignoring that it is discarding 99% of requests to it. No sane engineer would think things are getting better if the report drops to 24%, given the full context.