Did some quick research on these issues that you touched on in japan.

A few professors wrote a paper on why the Japanese conviction rate is so high, they concluded it was because of two reasons. One is that judges who come under the control of central bureaucracy are pressured to pass a guilty verdict, ensuring high conviction. Another is that, given that non jury system (there isnt a jury system in japan) under inquisition system has predictable ruling on guilt, prosecutors rarely ever bring a case which have even minute chance of failure.

The paper found that Japanese prosecutors have a far more pressing need to be selective. In the U.S., the federal government employs 27,985 lawyers and the states employ another 38,242 (of which 24,700 are state prosecutors). In Japan, with about a third of U.S. population, the entire government employs a mere 2,000. Despite Japan having a low crime rate, such numbers create a significant case overload for prosecutors. In the U.S., there are 480 arrests (96 serious cases) per year per state prosecutor. (The actual figure is lower as some are prosecuted in federal court). In Japan, the figure is 700 per year per prosecutor. In the U.S., a rough estimate is that 42% of arrests in felony cases result in prosecution - while in Japan, the figure is only 17.5%.

The Japanese criminal justice system, despite retaining the death penalty, is relatively lenient in sentencing by the standard of the United States. Outside capital cases, many of those sentenced to life sentences are paroled within 15 years. Those convicted of less heinous murder and manslaughter are likely to serve less than 10 years. Those convicted of rape will often serve less than two to five years. It is even possible for someone convicted of murder to serve a suspended sentence if the defense successfully argues for mitigating circumstances. Moreover, in Japanese criminal proceedings the conviction and sentencing phase are separate.

http://www.rasmusen.org/published/Rasmusen-01.JLS.jpncon.pdf

On your point about the suicide numbers, there are a few reasons for that. Factors resulting in suicide include unemployment (due to the long economic recession), depression, and social pressures.In Japanese culture there is a long history of honorable suicide, such as ritual suicide by Samurai to avoid being captured, flying one's plane into the enemy during WWII, or charging into the enemy fearlessly to prevent bringing shame on one's family. Japanese society's attitude toward suicide has been termed "tolerant," and in many occasions suicide is seen as a morally responsible action.

And on your last point, I would much rather do the opposite. Have no national tragedies, etc even if it means I have to give up some of my individual rights to guns and lose some of my privacy because lets be honest we have very little privacy nowadays anyways and if an individual is extremely concerned about these issues then that tells me that person is somebody that should be monitored cause they might be up to something or there is a reason that they take these issues to heart most of the time.