From my experience, players don't rigidly stick to them anyway. Or endlessly look for ways to justify how their behaviour falls under the alignment.
What I *am* a fan of are reputation systems. The world and NPC's responding to the outcomes of your choices and behaviour.
Murder everyone in a village? Maybe you've done a great service to an invading warlord, who now wants to hire you. Maybe you've now got a bounty on your head from the local lord. Maybe you've accidentally killed someone with hidden knowledge and are now being tracked by people who want that secret.
Saved the village from raiders? The evil cultists operating in the village get to continue their plans. A young hero survives the raid and joins your party. The local mayor grants you a plot of land in gratitude.
That's the real power of making decisions, not this weird restriction around what you "should and shouldn't do based on a decision at character creation".