I probably wouldn't use a NOT DEATH NOTE. If I'm convinced that murder is the best solution to a situation, I feel like I should take responsibility for that murder, too.
It's actually remarkably hard to instigate change via death. Take a political a revolution, for example. Most of the names you actually need to kill are not politicians, but the political donors. Politicians have a chain of succession. Political donors do not.
Just think about the can of worms killing a donor opens: before you kill them, you need to know all sorts of things like who their heirs are (and in what proportions), who those heirs would likely donate to, and what kind of estate taxes they'd face. This is comlicated by the fact that most rich people don't publicize their wills, and have charities as major recipients. Another major subset of political donors are businesses, and again you face chain of command problems.
Put bluntly, using this thing effectively requires an absurd amount of research. Some of the necessary information will be almost impossible to get legally and the very fact you are researching it will probably reveal your hand eventually.
