Alignment was even used as a balance element. Paladins were simply more powerful than their fighter counterparts but this was justified because of the higher ability requirements (which really just made the balance issues worse) and a strict code of conduct related to the alignment system.
Somewhere along the way, this sort of alignment system got a bad reputation. Maybe most fundamentally, the alignment dimensions in ADnD were difficult to define. As someone who has invested an immodest amount of time reading moral philosophy, I never could get my brain around the simple 2D system. Other-regardingness (good) vs. self-regardingness (evil) was relatively simple but still at odds with many storylines. Totalitarian leads may be other-regarding (say for their country or ethnic group) but are archetypes of real world "evil."
The second dimension was even more difficult to define. One take was to define law as deference to authority (maybe communitarianism) and chaos as individualism (maybe libertarianism). Another take was to define law as deontological (morality by rights and rules) vs chaos as a consequentialist (morality by consequence, utility, etc.). These two approaches are not identical and neither is fully consistent with the written rules. This was just made worse with chaotic neutral basically defined as insanity.
Anyway, I am not going to disentangle this old system that has defied all simple redefinition and packing. I do think this was one of the reasons that many systems have moved away from alignment systems. There is basically no such system in the Cypher System.
I think, though, that something was lost in abandoning the pursuit of a coherent alignment system. The discussions between players about what sort of actions were consistent with their alignment were fruitful drivers of role playing. However a player defined their alignment, it served as a guidepost for their character's behavior. It may be been a clunky system but it was one that was at the core of the role-playing component of the game.
I anticipate writing a few posts about various attempts to fill the gap left by the absence of the alignment system.
Before I get started, though, I am curious. Is this something you feel is missing in your Cypher games?