In my youth I thought the alignment system in AD&D, with its vaguely pseudo-Judeo-Christian viewpoint, was a brilliant summary of morals and ethics in a systematic way. Of course adulthood has a way of wiping away the simplistic views of youth as you learn how complicated morals and ethics (philosophy) really is. Also, in college my philosophy professor was a Zen Buddhist. Talk about adding a twist to the whole question of philosophy!
One of the things held against basic D&D was that it's alignment system was too simple (and of course that race-as-class wasn't as cool as race + class).
But now I appreciate the elegance of original D&D and the general line of "basic" D&D. I think one of the best things it had going for it was that the management at TSR didn't pay much attention to it, so Frank Mentzer and co. were allowed to go their own creative way. And I really like how it pays homage to the original set. Still I like to ponder how to improve the alignment system, as unrealistic as it may be.
One approach I am mildly fond of is Palladium where different alignments are given specific names. It adds flavor: Principled, Anarchist, Diabolic, etc. With that in mind, and in the spirit of Gygaxian systematization here is another way to look at alignment.
What if we added another layer to the axis of Law/Chaos, Good/Evil and added Zealotry/Indifference. So someone could be mildly Lawful Good, or ZEALOUSLY Lawful Good! This chart would look something like this with concentric circles radiating out from Neutrality, the innermost circle representing Indifference and the outer circle representing Zealotry.