Besides the clinical analysis already posted, one aspect always bugged me about accusing Bruce Wayne/Batman of not doing something "more productive" than dressing up in a costume:
He is doing something besides being Batman.
In most continuities Wayne Corp and the Wayne Foundation are portrayed as massive philanthropic enterprises. It seems reasonable to assume that as Bruce Wayne, Batman is funding plenty of good works for society with his fortune. At various times the foundation has funded social work, infrastructure, civilian charities, and the actual police and government in Gotham City. Of course, it could be argued that the effectiveness of this is downplayed in order that Gotham remain crime ridden and dark, so that Batman has an appropriate environment to prowl around in.
And that's a fair claim. But it doesn't change the fact that Batman doesn't just run around in costume. It could be logically inferred that he already does everything a "normal" person with a lot of wealth could do in order to encourage a better society. This seems to back up the idea that Batman's problem isn't that he's insane, irresponsible, or doing the wrong thing to help society. His emotional attachment to his life experiences drives him to do something yet further beyond what he can do as a (wealthy) private citizen.