The Age of Reason
Alignment can act as a way to help you guide the way your character acts, however, it should not be treated as a hard and fast rule. As such, we will be lessening the effect of spells and other effects that rely on alignment. Any spell of effect that relies on chaotic or lawful (such as axiomatic weapons, detect chaos, or the like) will be removed. Things that rely on the good/evil alignment will still be in effect, but with a small change.
I will be using a system of Taint, where Taint is left on your soul when you commit evil acts. If a character has enough Taint on them, then they will be effected by things like Smite, Detect Evil, etc. The same applies to those that do not have Taint, and spells and effects that target good creatures, etc. There are not going to be hard and fast rules or measurements of Taint, there will be judgement calls based on your backstory and your actions in the course of the campaign. For example, if you kill an innocent person (even by mistake), you will start to register some level of taint without your character knowing. Enough of acts like this and your effective alignment for spells and effects will shift. Atonement spell can be used to remove Taint, as can good acts, especially correcting wrongs that were the initial cause of Taint.