As for your game idea: the problem is that a system that it not only makes it so the player does the right thing just to score points, it's also a fairly cheap way say that what you're doing is wrong.
Alternatively players simply won't care, it just becomes a bar that shifts around on the side.
Good point. The other way around would be to have an invisible meter and have the player's actions be reflected into the game. Different types of news stories and pedestrian talk based on what the player has done.
Actually, I would like to avoid a clear cut good/evil and try to make it something more subtle. Some of the police force is corrupt, some of the gangs are not doing anything illegal (or at least nothing major.) No clear announcements of "YOU HAVE GAINED KARMA!" Army of Two 40th day had a good idea where doing the apparently good thing would sometimes backfire or end up not having any effect. Some people hated it but I like the idea, things weren't as simple as they appeared to be.
Black and White and Infamous games had a good idea of making the morality affect the player and their surroundings. (with variable degrees of success...)
Another important point would be that I would want it to be more than just OH SO EDGYNESSS!!! For example, the game should be dark and have the player characters inevitable death looming on the horizon but the whole point of the game should be about making certain that the death will not be meaningless. Wether it would be because they ensure that their family will have money, that they take out some bad guys with them (Punisher styles crusade against evil that may, or may not inspire others), trying to use the money to get an expensive "miracle" cure or simply that they leave such a pile of bodies that they will be remembered in infamy. So basically, that last possibility would allow the player to do what the HATrED is all about, but it would only be one option. And for the love of L. Ron Hubbard at least there would be some motivation (even if it is I AM AFRAID TO DIE AND WILL LASH OUT AT THE WORLD) rather than "I AM SOOO EDGY AND DARK AND NIHILISTIC!"
...But it is not like I could ever make that game. Not even sure if it has potential.