I think it's hard to judge, and there is no clear side where he is on, "good" or "evil". Because most people or emotions or actions are too complex to be black or white.
Lights intentions are good, he wants to clean the world of criminals. His actions however, by blatantly killing them off, are morally wrong. Morally.
Of course he gets spoiled by his big ego and hunger for might and power, which leads to his downfall.
But I still think his intentions were good.